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In mechanical applications, defect-based fatigue cracking is a significant strength-limiting failure mode of additively manufactured composites that is not yet fully understood in the service environment. In this paper, axial loading tests were carried out at 25 ℃ and 450 ℃, and then the effects of temperature on the long-life fatigue properties of the TiC-reinforced Ti6Al4V composite fabricated by Laser Powder Bed Fusion (LPBF) were investigated by combining the techniques of electron backscatter diffraction, X-ray computed tomography, and 3D morphological reconstruction. With the increase in temperature, the fatigue strength of the LPBF TiC/Ti6Al4V composite decreases significantly. The main causes of the interior failure at both temperatures are the inhomogeneous hardening zone (IHZ) formed by TiC agglomeration and the pore defect generated during the manufacturing process. The presence of brittle IHZ and pores causes stress concentration, which leads to crack nucleation. When a crack reaches the specimen surface, the combined effects of temperature and oxygen accelerate the ensuing crack propagation at high temperature. Based on the temperature effect, material properties, and the statistical distribution of defects, a model has been developed to predict the P-S-N curves at both temperatures. This model performed well in estimating the fatigue strength at 109 cycles. These findings provide new insights into the defect-related fatigue failure mechanisms and strength evaluation of the LPBF TiC/Ti6Al4V composite at different temperatures. [Display omitted] • Two defect-based cracking modes with IMZ-fisheye are revealed. • One cracking is attributed to the aggregation and debonding of TiC particles. • The other cracking is due to the irregular pores formed during LPBF. • A strength evaluation model with statistical defect size is proposed. [ABSTRACT FROM AUTHOR]

Reactive materials are functional structural materials that balance structural strength and reactivity, and their shock response is greatly influenced by the characteristics of reactive components. This article aims at understanding the shock compression and reaction of Al-Hf reactive materials with two values of the Al-Hf particle size ratio α (1 µm:10 µm and 10 µm:10 µm), which were prepared through hot pressing with a compactness (the ratio of density to theoretical maximum density) greater than 96.46%. The free surface velocity of the materials was measured in the impact velocity range of 279–865 m/s. The Hugoniot elastic limit (HEL), spall strength, and Hugoniot relationships under shock stresses of 1.83–14.46 GPa were analyzed on the basis of the microstructure and phase change. Continuous Al phase was formed in the sample with α = 0.1, while more Hf–Hf contact and crushed Hf appeared in the sample with α = 1. The velocity profiles presented clear signs of the linear growth to the HEL, the slow increase to the peak, and the subsequent pullback, indicating the transition from elastic to plastic and spall behavior. The HEL fluctuated significantly with increasing shock stress, while the spall strength first increased and then decreased. The sample with a continuous Al phase exhibited a lower HEL (0.52–0.97 GPa) and higher spall strength (0.31–0.46 GPa). The microstructure had a significant effect on the shock induced chemical reaction of the materials. Shock velocity was linearly related to particle velocity for the α = 0.1 sample, while a notable quadratic growth was observed for the α = 1 sample owing to self-reactions under the lower shock stress (5.32 GPa). The intermetallic Hf 4 Al 3 observed in the recovered product by X-ray diffraction further verified the phenomenon. • Nearly fully dense Al-Hf reactive material was prepared by hot pressing. • The effect of microstructure on the shock behaviors and reaction characteristics was investigated. • The sample with larger particle size of Al exhibited higher Hugoniot elastic limit and lower spall strength. • Intermetallic Al 4 Hf 3 was observed in the recovered samples, and sample with larger Al are more prone to reactions. [ABSTRACT FROM AUTHOR]

SnO 2 -based anode of lithium-ion batteries (LIB) suffers from excessive volume expansion and low conductivity, resulting in very poor capacity stability and rate capability. To solve the problems, three kinds of SnO 2 /Sn@carbon heterostructures were synthesized by a salt template following calcination using tartaric acid, p-phthalic acid and ethylenediamine tetraacetic acid with different carboxyl groups as carbon sources, respectively. The acidity, carbon atoms number and position affect the ratio of SnO 2 /Sn, the morphology and content of derived carbon, the advantage crystal plane and the surface defects of SnO 2. The carbon atoms located at carboxyl are transformed to CO and formed pores, and the carbon atoms at alkane chain are polycondensed and transformed to amorphous carbon during annealing process. The SnO 2 /Sn@C derived from tartaric acid (SnO 2 /Sn@TA) has the largest ratio of SnO 2 /Sn, which fixed on graphene-like porous carbon, exposed the most surface defects and more high energy crystal plane. The specific structure ensures structural stability and ultrahigh capacity, lower Li+ diffusion barrier energy and super rate capability. It exhibits the charge/discharge capacity of 1059.7/1064.4 mAh g−1 at 2 A g−1 after 1500 cycles and super rate performance of 399.3/404.5 mAh g−1 at 6 A g−1, which are superior to most reference data. [Display omitted] • Different heterostructures of SnO 2 /Sn@graphene-like porous carbon was synthesized. • C atoms at -COOH transform to CO to create pores, at alkane chain into amorphous C. • SnO 2 /Sn@C heterostructure decreases Li+ diffusion distance and barrier energy. • SnO 2 /Sn@C exhibits ultra-high capacity of 1064 mAh g−1 at 2 A g−1 for 1500 cycles. [ABSTRACT FROM AUTHOR]

Forming nanocomposites among different metal oxide species may lead to gas sensors with superior gas sensing properties. In this work, terbium oxide (Tb 2 O 3) was used to form composite nanofibers with zinc oxide (ZnO) to detect nitric oxide (NO) gas. The Tb 2 O 3 /ZnO composite nanofibers were synthesized through a facile electrospinning and annealing treatment. The heterostructure was investigated by various techniques such as XRD, SEM, TEM, and XPS, whereas the gas sensing performance of the composite nanofibers was investigated with a static gas testing system. Results showed that the Tb 2 O 3 /ZnO composite nanofiber exhibited excellent sensing performance to NO at 180 °C. Specifically, the composite nanofiber with [Tb]/[Zn] molar ratio of 0.01 had a high response of 28.3 (resistance ratio) to 1 ppm NO gas at 180 °C, with low response to other interference gases. The sensor also exhibited good repeatability and long-term stability. These remarkable sensing properties indicate that conventional ZnO is still promising for real applications via material composition and structure. • The Tb 2 O 3 /ZnO composite nanofibers can be synthesized through a facile electrospinning and annealing treatment. • The Tb 2 O 3 /ZnO composite nanofibers possess more abundant surface-adsorbed oxygen species than pure ZnO nanofibers. • The Tb 2 O 3 /ZnO composite nanofibers show better sensing properties than pure ZnO nanofibers. • The sensing mechanism of Tb 2 O 3 /ZnO composite nanofibers is related to the formation of p-n hetero-junction. [ABSTRACT FROM AUTHOR]

Herein, sandwich-like Ti 3 C 2 T x MXene/SnO 2 quantum dots composites were synthesized as sulfur host, aiming to alleviate the shuttle effect of polysulfides present in lithium-sulfur batteries. SnO 2 quantum dots (SnO 2 QDs) were introduced into the interlayer of MXene through a simple electrostatic self-assembly method, and the mass fraction of SnO 2 QDs was controlled to construct sandwich MXene/SnO 2 QDs. While SnO 2 QDs effectively alleviating the stacking tendency of MXene, Ti and Sn co-chemisorb polysulfides and the interlayer structure physically confines polysulfides. Significantly, the synergistic effect between MXene with SnO 2 QDs effectively alleviates the shuttle effect of polysulfides and buffers the volume expansion. Meanwhile, with the help of the catalysis of SnO 2 QDs, the liquid-solid reaction kinetics of lithium polysulfides converting to Li 2 S 2 /Li 2 S is accelerated. Electrochemical test results showed that the MXene/SnO 2 QDs/S cathode has a high initial discharge specific capacity (1147.6 mAh g−1 at 0.1 C, while MXene/S is only 615.4 mAh g−1), as well as excellent rate performance and cycling stability in Li-S batteries. • Sandwich-like Ti 3 C 2 T x MXene/SnO 2 QDs composites were successfully synthesized as sulfur host in lithium-sulfur batteries. • The Ti 3 C 2 T x /SnO 2 QDs effectively alleviates the shuttle effect of polysulfides and buffers the volume expansion. • The MSn/S has a high initial discharge specific capacity (1147.6 mAh g−1 at 0.1 C, while MXene/S is only 615.4 mAh g−1). [ABSTRACT FROM AUTHOR]

Transition metal phosphides are considered as promising alternatives to noble-metal based electrocatalysts for water splitting due to their bifunctional catalytic activity. The modulation of morphology and electronic structure is an efficient strategy to improve the mass transport and electronic conductivity of metal phosphides, but still faces a great challenge to achieve this conjoint regulation. Herein, a facile Zn-doped strategy was developed to synthesize cobalt phosphide (CoP) catalyst with thickness-controlled porous nanosheet structure. At the current density of 10 mA cm−2, the optimized Zn 0.1 -CoP catalyst delivers an overpotentials of 290 mV and 98 mV for OER and HER, respectively. The cell voltage for the overall water splitting is 1.57 V to reach the current density of 10 mA cm−2, outperforming the counterparts of noble metal-based Pt/C and IrO 2 catalysts. The density functional theory (DFT) calculations reveal that Zn doping can effectively improve the conductivity and regulate the electronic structure of CoP, thus resulting in fast charge transfer transport and reduced energy barrier of the rate-determining step. This work provides a favorable strategy for the rational design of bifunctional catalysts with high-performance for overall water splitting. [Display omitted] • The Zn-doped CoP electrocatalysts with controllable morphology and electronic structure have been facilely synthesized • Zn-doped CoP porous nanosheets and its in -situ transformed Zn-CoOOH exhibit enhanced catalytic properties • The electronic structure and intrinsic catalytic activity of CoP can be finely regulated by Zn doping • The designed Zn 0.1 -CoP catalyst shows superior water-splitting performance to the commercial Pt/C-IrO 2 catalysts [ABSTRACT FROM AUTHOR]

Ultrasonic surface rolling processing (USRP) was performed on a Mg–Y–Nd–Zr alloy after equal-channel angular pressing. The result shown that the surface roughness was significantly improved, residual stress was introduced to the topmost surface, and ~450 µm gradient nanostructure (GNS) of Mg alloys was obtained after USRP treatment. The mechanism of microstructure evolution and its effect on the mechanical properties of the Mg alloy were studied in detail. There are multiple deformation mechanisms in grain refinement. In the initial stage, the coarse-grain (CG) matrix was subdivided by {10 1 ̅ 2}< 10 1 ̅ 1 > extension twins. Subsequently, the deformed grains were refined into substructures using interaction between twins, interaction between twins and dislocations, and dislocation entanglement. Moreover, the substructure contains a high density of multiple stacking faults and dislocation arrays, which can effectively block dislocation movement and promote dislocation packing. Finally, equiaxed nanograins (NGs) with high-angle grain boundaries were formed via subcrystal rotation recrystallization. With the formation of a GNS, the strength of the Mg–Y–Nd–Zr alloy considerably increased at the expense of a small amount of plasticity. The tensile test results demonstrated that the yield strength (YS) and ultimate tensile strength (UTS) of the Mg–Y–Nd–Zr alloy increased from 171.96 and 262.47 MPa to 216.06 and 330.61 MPa, respectively, and the elongation rate decreased from 20.52% to 14.65% after the USRP treatment. The YS improvement of the Mg–Y–Nd–Zr alloy after the USRP treatment was attributed to grain boundary strengthening, synergistic strengthening, dislocation strengthening, and twin strengthening. Furthermore, the microhardness of Mg–Y–Nd–Zr considerably improved after USRP treatment, and grain refinement was the primary surface strengthening mechanism of the Mg–Y – Nd – Zr alloy after the USRP treatment. The work-hardening capacity of the Mg alloy improved after the USRP treatment, and the synergistic deformation between GNS and CG matrix was the primary reason for the excellent work-hardening capacity of the Mg–Y–Nd–Zr alloy. • The gradient nanostructure of Mg alloys was obtained by ultrasonic surface rolling processing. • The microstructure evolution mechanism of Mg alloys during ultrasonic surface rolling processing was discussed in detail. • The surface strengthening mechanism of Mg alloys after ultrasonic surface rolling processing was discussed in detail. [ABSTRACT FROM AUTHOR]

The NiCr/Al nanomultilayered films with different Al thicknesses (t Al) were prepared by magnetron sputtering. The structural evolution of the Al nanolayer with the increase in t Al was investigated. When the Al layer thickness changed from 1.2 nm to 2.4 nm, the Al layer could keep the co-epitaxial growth with the adjacent NiCr layer. Accordingly, the crystallization degree improved. When the Al layer thickness changed from 2.4 nm to 3.0 nm, the transformation from the coherent to incoherent interfaces took place between the NiCr and Al layers. Meanwhile, the co-epitaxial growth with the adjacent NiCr nanocrystallites was destroyed, the crystallinity and the grain size decreased, leading to the increase of the resistivity under the combined effects of the grain boundary scattering and interface scattering. The interfacial evolution of NiCr/Al nanomultilayered films was closely related to the changes of electrical properties. When the Al layer thickness changed from 3.0 nm to 3.6 nm, the surface quality of the film was improved, which effectively reduced the scattering of defects and vacancies during the electron transport, resulting in the decrease of the resistivity of the NiCr/Al nanomultilayered film. [Display omitted] • Al films inserted NiCr nanolayers with different thickness were synthesized. • The microstructure structure of NiCr was damaged with insertion of Al nanolayers. • The resistivity was renewedly increased with the change of interface structure. • The resistivity later deteriorates with the improvement of the surface quality. [ABSTRACT FROM AUTHOR]

• MoS 2 containing crystal water is synthesized by a simple hydrothermal method. • The electrochemical performance of the MoS 2 with/without crystal water are tested to further understand the role of crystal water in MoS 2. • Due to the lubrication and support of crystalline water, the MoS 2 ·nH 2 O electrode delivers a high specific capacity and satisfactory cyclability. • The polarization resistance change of MoS 2 ·nH 2 O and MoS 2 -400 in the aqueous zinc ion batteries was calculated through the DRTtoolbox in MATLAB. MoS 2 ·nH 2 O was synthesized by a simple hydrothermal method, and the unique nanoscale flower structure combined with the lubricating effect of crystal water make it exhibit good capacity and stability in aqueous Zn2+ ion batteries. [Display omitted] As a special group of two-dimensional layered compounds, transition metal dichalcogenides (TMDs) have attracted great attentionfor rechargeable zinc ion batteries (ZIBs). However, the large zinc ion radius, the strong electrostatic interaction with the host material, and the slow dynamics of Zn2+ limit the application of TMDs in rechargeable aqueous ZIBs. Herein, MoS 2 ·nH 2 O is synthesized through a facile hydrothermal reaction. The unique nanoscale flower structure combined with the introduction of crystal water can reduce the electrostatic interaction between zinc ion and skeleton, promote the diffusion of zinc ion, and effectively accelerate the reaction kinetics. Benefiting from the above advantages, the MoS 2 ·nH 2 O electrode exhibits a high rate capacity and satisfactory cyclability (88% capacity retention after 800 cycles at 2 A g−1). The excellent performance of MoS 2 ·nH 2 O proves that the introduction of crystal water is a practical strategy to promote the hydration kinetics of large-size multivalent ions, which may provide a viable and attractive solution for the synthesis of other cathode materials for aqueous ZIBs. [ABSTRACT FROM AUTHOR]

ZrN and TiNiN nanolayers are alternately deposited on silicon substrate by magnetron sputtering. A series of ZrN/TiNiN nano-multilayer films with different Ni contents are prepared by varying the Ni:Ti volume ratio of the targets. The effects of Ni content on the microstructures and mechanical properties of ZrN/TiNiN nano-multilayer films are studied by X-ray diffractometer (XRD), scanning electron microscopy (SEM), high resolution transmission electron microscopy (HRTEM) and nanoindentation instrument. The results show that with the increase of Ni content, the crystallization degree of ZrN phase first increases and then decreases. Besides, the hardness, elastic modulus and toughness of the films also increase first and then decrease with Ni content increasing. When Ni:Ti= 1:24, the ZrN/TiNiN nano-multilayer films obtain the highest hardness, elastic modulus and fracture toughness, which are 23.2 GPa, 317.8 GPa and 2.29 MPa·m1/2, respectively. This is mainly attributed to the best columnar crystal growth of the ZrN/TiNiN nano-multilayer film. The TiNiN layer changes into face centered cubic structure under the template of ZrN layer, and grows in coherent epitaxy with ZrN layer. ● A series of ZrN/TiNiN nano-multilayer films with different Ni contents are prepared by magnetron sputtering. ● When Ni:Ti= 1:24, the ZrN/TiNiN nano-multilayer films simultaneously obtain the highest hardness and fracture toughness. ● The high hardness and toughness are due to that the TiNiN layer grows in coherent epitaxy under the ZrN layer template. [ABSTRACT FROM AUTHOR]

Semiconductor heterostructures are one of the most promising materials for hydrogen energy production. However, the low hydrogen production rate of current materials becomes a bottleneck. To this end, we designed an interface redox-induced synthesis (IRIS) approach to fabricate SrTiO 3 /α-Fe 2 O 3 heterojunction with broadband absorption for efficient hydrogen production by the photolysis of water. The hydrogen production rate and output reached 9.8 mmol g−1 h−1 and 235.2 µmol, and the hydrogen production in 12 h of the material from the IRIS approach was 47 times higher than that of similar materials fabricated from other methods. Detailed experimental characterization and theoretical computation revealed that the much-improved performance is contributed by the tight bonding of two materials and the desired band structure at the interface. The working mechanism and the synthesis approach provide an essential guideline for designing photocatalysts for renewable energy, water treatment, and other applications. Synthesis of SrTiO 3 /α-Fe 2 O 3 HNCs with excellent morphology, while α-Fe 2 O 3 is uniformly distributed on SrTiO 3. [Display omitted] [ABSTRACT FROM AUTHOR]

SnS is regarded as an ideal material for electrodes in next-generation lithium-ion batteries (LIBs) due to its high specific capacity and low cost. However, the low conductivity and larger volume expansion during charge/discharge hinder its practical application. In this paper, a novel core-shell tremella fuciformis shaped SnS@Sulfur doped carbon composite (SnS@C) was constructed by reduction of as-prepared nanoflower SnS 2 and carbonazation of carboxymethyl cellulose using a crystallized NaCl as template under N 2 atmosphere. The sulfur doping carbon shell with more defects can increase not only the electrical conductivity but also enhance the mechanical strength of the SnS@C due to the larger space provided by interconnected tremella fuciformis shaped structure, as well as can provide more active sites for lithium-ions intercalation/de-intercalation by surface pseudocapacitive behavior. It remains stable capacity of 1078 mAh g−1 cycled at 0.2 A g−1 after 200 cycles, and 801 mAh g−1 even at 1.0 A g−1 for 500 cycles, and 403 mAh g−1 even at 5 A g−1 of rate performance. The simple synthesis scheme not only creates more reactive sites, but also forms a stable 3D interconnected carbon skeleton structure, which is suitable for other energy storage and conversion materials too. [Display omitted] • A core-shell tremella fuciformis shaped SnS@S doped carbon composite was obtained. • S doped carbon shell was obtained by a simple reduction of SnS 2 and carbonization method. • S doping of carbon enhance the defects and favor for Li+ storage as surface pseudocapacitive. • The carbon shell of SnS@C increases the conductivity and stablize the SnS structure. • 3D interconnected petals provide large space and more active sites for Li+ storage. [ABSTRACT FROM AUTHOR]

SnS is regarded as an ideal material for electrodes in next-generation lithium-ion batteries (LIBs) due to its high specific capacity and low cost. However, the low conductivity and larger volume expansion during charge/discharge hinder its practical application. In this paper, a novel core-shell tremella fuciformis shaped SnS@Sulfur doped carbon composite (SnS@C) was constructed by reduction of as-prepared nanoflower SnS 2 and carbonazation of carboxymethyl cellulose using a crystallized NaCl as template under N 2 atmosphere. The sulfur doping carbon shell with more defects can increase not only the electrical conductivity but also enhance the mechanical strength of the SnS@C due to the larger space provided by interconnected tremella fuciformis shaped structure, as well as can provide more active sites for lithium-ions intercalation/de-intercalation by surface pseudocapacitive behavior. It remains stable capacity of 1078 mAh g−1 cycled at 0.2 A g−1 after 200 cycles, and 801 mAh g−1 even at 1.0 A g−1 for 500 cycles, and 403 mAh g−1 even at 5 A g−1 of rate performance. The simple synthesis scheme not only creates more reactive sites, but also forms a stable 3D interconnected carbon skeleton structure, which is suitable for other energy storage and conversion materials too. [Display omitted] • A core-shell tremella fuciformis shaped SnS@S doped carbon composite was obtained. • S doped carbon shell was obtained by a simple reduction of SnS 2 and carbonization method. • S doping of carbon enhance the defects and favor for Li+ storage as surface pseudocapacitive. • The carbon shell of SnS@C increases the conductivity and stablize the SnS structure. • 3D interconnected petals provide large space and more active sites for Li+ storage. [ABSTRACT FROM AUTHOR]

First, UV stopped-flow profiles were measured upon rapid mixing a series of soluble metal salt precursors with the Na 2 CO 3 solution to detect the kinetics of the complicated process involving the insoluble material formation reaction and the subsequent nanoparticles growth. Comparing the kinetic curves in 60 ms with 300 ms at 45–65 °C, it illustrates that the formation reaction of insoluble transition metal carbonates occurs rapidly (shorter than 60 ms) and precipitates as nanoparticles that act as the seeds for the subsequent particle growth. Then, a High-Shear co-Precipitation (HSP) method was developed to synthesize uniform LiNi 0.6 Co 0.2-x Mn 0.2 La x O 2 , overcoming the inherent difference of tens of magnitude in the solubility product constant (K sp) of individual carbonates. The synthesized LiNi 0.6 Co 0.198 Mn 0.2 La 0.002 O 2 exhibits an initial discharge capacity of 200.5 mAh g−1, superior to LiNi 0.6 Co 0.2 Mn 0.2 O 2 (194.7 mAh g−1, 0.1 C). In addition, the phosphorous coating of LiNi 0.6 Co 0.198 Mn 0.2 La 0.002 O 2 increased the capacity retention up to 86.4 % (400th, 5 C). DFT calculations indicate that La-intercalation can enlarge the Li+ layer spacing and reduce the Li+ migration energy barrier. This work illustrates the importance of the pulverization effects exerted by the High-Shear force on various insoluble nanoparticles during the initial rapid mixing period, providing a useful tool for manufacturing heteroatom-intercalated bulk nickel-rich cathode material. [Display omitted] • Insoluble carbonates nanoparticles are mixed evenly by ultrafast High-Shear force. • LiNi 0.6 Co 0.2-x Mn 0.2 La x O 2 is synthesized via a High-Shear co-Precipitation method. • LiNi 0.6 Co 0.198 Mn 0.2 La 0.002 O 2 shows an initial capacity of 200.5 mAh g−1 (0.1 C). • P-coating synergically improves the retention to 86.4 % (400th, 5 C). • La-intercalation enlarges the Li+ layer spacing of nickel-rich cathode. [ABSTRACT FROM AUTHOR]

The hydrogenation kinetics of Sm 26.2 Co bal Fe x Cu 4.0 Zr 2.3 (x = 23, 27 in wt%) strips (Fe23 and Fe27 strips) has been investigated. The phase composition, morphology, surface roughness and the inner pores of the strips also have been studied by XRD, SEM, optical profilometer and non-destructive micro-computerized tomography. Compared to Fe23 and Fe27 strips, heat-treated strips (H-Fe23 and H-Fe27) and corrosion heat-treated strips (HC-Fe23 and HC-Fe27) exhibit a relatively higher hydrogen absorption capability. Fragmentation behavior occurs in HC-Fe23, H-Fe27 and HC-Fe27 strips during hydrogenation. After heat treatment, the grain size and inner pore size increase, leading to the disappearance of fine crystal strengthening and the concentration internal stress. For corrosion-treated strips, increased surface roughness and deeper grooves result in the formation of surface stress concentration, ultimately leading to an increased susceptibility to hydrogen embrittlement. Accordingly, the increase of grain size, inner pore size and rougher surface is beneficial for hydrogenation and hydrogen embrittlement. • The effect of heat- and corrosion- treatment on grain size, inner pores and surface roughness of the strips are - studied. • The reduced fine grain strengthening and pronounced internal stress concentration lead to a higher HAC. • Corrosion treatment promotes hydrogen absorption and the susceptibility of hydrogen embrittlement. [ABSTRACT FROM AUTHOR]

The production of effective photocatalyst to generate H 2 and eliminate pollutants is still a challenge. A simple solvothermal approach is demonstrated for synthesizing a coupled P-C 3 N 4 /MIL-88A(Fe) composite wherein two-dimensional phosphorus-doped g-C 3 N 4 nanosheets are attached to three-dimensional MIL-88A. The P-CN/MIL-88A composite shows superior photocatalytic ability with a high hydrogen generation rate of 34.53 mmol/(g·h) and an ofloxacin degradation rate of 95.6%. The H 2 evolution rate of the composite is approximately 38.3 times that of bulk g-C 3 N 4 (B-CN). The enhancement mechanisms resulting in high efficiency and adaptability are attributed to the Z-scheme (2D/3D) P-CN/MIL-88A heterojunction, which has unique synergistic interface properties, good photoinduced electron mobility, and good electron-hole pair separation ability. This work provides insights into the design of 2D/3D heterostructure photocatalysts for highly efficient and simultaneous photocatalytic H 2 production and antibiotic degradation. • A novel Z-scheme (2D/3D) P-CN/MIL-88A photocatalyst was prepared by solvothermal method. • The P-CN 300 /MIL-88A exhibits the superior photocatalytic performance for H 2 evolution and ofloxacin degradation. • The •O 2 and •OH are confirmed as the main reactive species in the photocatalytic activity. • The possible mechanism of photocatalytic was explored. [ABSTRACT FROM AUTHOR]

Two ternary heterojunction composites, namely hollow-structured TiO 2 /CdS/Au and hollow-structured TiO 2 /Au/CdS, were successfully synthesized by preparing hollow-structured TiO 2 first, followed by the deposition of Au and CdS (with different deposition sequences), respectively. In these two composites, hollow-structured TiO 2 nanotubes provide 1D structure with large specific area, which facilitate the immobilization of CdS and Au nanoparticles and the transfer of electrons. CdS is visible-light responsive and Au nanoparticles can improve photocatalytic efficiency by the formation of schottky barrier and surface plasmon resonance effect (SPR). The structures and phases, morphologies, surface and optical properties of the two composites were systematically characterized. TiO 2 /CdS/Au ternary heterojunction composite has efficient light absorption ability and excellent performances in photocatalytic hydrogen generation (up to 3600 μmol h−1 g−1), which is more than 4 times higher than that of TiO 2 /Au/CdS (800 μmol h−1 g−1). Therefore, in this way, we present a promising strategy to construct hybrid photocatalysts for hydrogen production. • Hollow-structured TiO 2 /CdS/Au and TiO 2 /Au/CdS heterojunction photocatalysts were synthesized. • TiO 2 /CdS/Au exhibited excellent visible-light activity on H 2 generation. • The hollow-structured TiO 2 /CdS/Au improved the separation and transfer efficiency of electrons. [ABSTRACT FROM AUTHOR]

To respond to the gradually increasing demand for thermal stability of sintered NdFeB magnets and grasp the evolution rules of their phase structure, research on sintered Nd-Dy-Fe-Co-B magnets was conducted. The magnets used in this study were prepared by the powder metallurgy method (Strip Casting + Hydrogen Decrepitation + Jet Milling). The room temperature magnetic properties of the magnet sample were B r = 11.45 kGs and H cj = 22.42 kOe, with a low-temperature coefficient of B r (α Br (20 °C∼100 °C) = −0.059 %/°C) and a high Curie temperature (T c = 460 °C). Based on the microstructure observation, there were planar anisotropic soft magnetic phase Nd 2 Co 17 within grain boundaries and the "Cu-Co Opposite Distribution". Low-melting-point binary alloy Pr 80 Cu 20 was introduced into the magnet by grain boundary addition to eliminate Nd 2 Co 17 phases and improve the coercivity. After the grain boundary addition, the "Cu-Co Opposite Distribution" was used to eliminate the Nd 2 Co 17 phase, the grain boundary structure was optimized, and the coercivity was increased by approximately 2.6 kOe, which was approximately 10 % of the total coercivity. Therefore, Cu-containing low-melting-point binary alloy grain boundary addition is an effective method for optimizing the grain boundary structure of Nd-Dy-Fe-Co-B magnets, thereby improving the high-temperature stability and coercivity. • The "Cu-Co Opposite Distribution" was found in the Nd-Dy-Fe-Co-B magnets. • The planar anisotropic soft magnetic phase Nd 2 Co 17 was found in grain boundaries. • Pr 80 Cu 20 binary alloy grain boundary addition is an effective method for optimizing the grain boundary structure. • The orientation behavior of sintered NdFeB magnets cannot be changed by the substitution of Co. [ABSTRACT FROM AUTHOR]

Crystallization of amorphous alloy is a commonly used method to fabricate nanocomposite permanent magnets. However, the effect of the hyperfine structures of amorphous alloy on microstructure evolution and magnetic properties of the obtained nanocomposites is far from understood. Here, amorphous Nd 9 Fe 85 B 6 alloys with different hyperfine structures, i.e., different short-range orders (R s = 0.80–0.91 nm), were prepared via melt spinning. The effects of the hyperfine structure on crystallization behavior, microstructure, and magnetic properties of the material upon thermal annealing were investigated in depth. Crystallization kinetics calculations show that a larger R s leads to a smaller apparent crystallization activation energy, which leads to higher volume fractions of α-Fe and Nd 2 Fe 14 B. At the same time, a crystallizaition process dependent stage crystallization activation energy of Nd 2 Fe 14 B has been obtained, which is low at nucleation stage and increases with crystallization process, i.e. easy for nucleation but hard for growth, which leads to a smaller grain size of Nd 2 Fe 14 B. As a result, optimized magnetic properties were obtained in the sample with R s = 0.91 nm. • Amorphous magnetic alloys with different hyperfine structures were prepared. • A larger short-range order (R s) leads to higher contents of two main phases. • A larger short-range order leads to smaller grain size of Nd 2 Fe 14 B phase. • Crystallization kinetic was investigated to explain microstructure evolutions. • Optimized magnetic properties were obtained in the sample with R s = 0.91 nm. [ABSTRACT FROM AUTHOR]

Here, we study the homogenization behavior and microstructure of seven Ni-Al-Ti alloys with quaternary additions of γ forming elements 4Cr, 4Co, 4Ru, 4Mo, 4Hf, 4 W and 2Re. To design a homogenization treatment, the as-cast microstructure is analyzed revealing the diffusion distances x between dendrite cores and interdendritic regions. The temperatures for homogenization are determined using differential scanning calorimetry (DSC) and Thermo-Calc simulations, to be between 1150 and 1275 °C. The time to achieve homogenization is modelled based on the residual segregation index δ utilizing diffusion distance, homogenization temperature and diffusion data. Electron probe micro analyzer (EPMA) measurements show that our predictions match for the 4Cr, 4Co, 4Ru, 4 W and 2Re alloys while the 4Hf alloy shows insufficient homogenization. Transmission electron microscopy (TEM) reveals a two-phase γ/γ' microstructure after 750 °C / 24 h, whereby the 4Co and 4Ru alloys form hierarchical microstructures. We observe γ plates in the 4Co alloy and γ spheres in the 4Ru alloy. Ru in the 4Ru alloy is involved in stabilizing the morphology of γ spheres. We provide a straightforward method for the design of homogenization treatments of Ni-based superalloys and demonstrate an alloy design pathway for tailoring the phase stability of hierarchical microstructures. [Display omitted] • Residual segregation index δ modelled and compared to experimental data. • Reaction temperatures from DSC and ThermoCalc. • Suitable homogenization treatments were designed. • Co and Ru promote formation of hierarchical microstructures. [ABSTRACT FROM AUTHOR]

Organic fluorescent dyes, as non-rare-earth phosphors, are crucial in the field of optoelectronic devices but significantly impeded by inherent strong aggregation-caused quenching effects and low thermal stability. To address these problems, herein, we devise a high-performance organic-inorganic composite phosphor consisting of ordered multilayer boron nitride (BN) nanosheets as a support that simultaneously improves the optical properties and thermal stability of acridine orange (AO). Besides, the emission intensities and colors of BN/AO composite phosphors can be adjusted by controlling AO concentrations and annealing temperature. In particular, the BN/AO composite phosphor displays strong yellow-green emission after 250 °C annealing. These findings offer a new avenue for the establishment of organic-inorganic hybrid luminescent materials. • Ordered multilayer BN nanosheets were synthesized using melamine foam as template. • The introduction of BN can improve the thermal stability of OA dye. • The optical properties of BN/AO composites can be turned by adjusting the AO concentration and annealing temperature. • BN/AO composite phosphors possessed excellent thermal stability. [ABSTRACT FROM AUTHOR]

• A novel α-SnWO 4 /UiO-66(NH 2)/g-C 3 N 4 ternary photocatalyst was prepared by solvothermal method. • The α-SW 75 /UNCN exhibits the superior photocatalytic performance for Ibuprofen degradation and H 2 evolution. • The •O 2 - and •OH are confirmed as the main reactive species. • The possible mechanism of photocatalytic was explored. [Display omitted] In this work, we successfully prepared regular hexagonal prism porous structure g-C 3 N 4 (CN), and designed α-SnWO 4 and UiO-66(NH 2) on porous CN for constructing novel ternary α-SnWO 4 /UiO-66(NH 2)/g-C 3 N 4 (α-SW/UNCN) hybrid photocatalyst by solvothermal approach. The α-SW 75 /UNCN composite showed better photocatalytic performance, and the removal rate of Ibuprofen (IPF) reached 95.5% within 2 h and the H 2 evolution efficiency reached 2105 μmol g−1 h−1 under simulated sunlight, which were 2.5 times and 21 times higher than those of α-SW (42.5% and 105 μmol g−1 h−1). The TOC removal efficiency of IPF can reach to 29%, showing higher mineralization ability compared with α-SW. In addition, the trapping experiment and ESR experiment proved that •O 2 - and •OH radicals played most important part in the photodegradation of IPF pollutants. The improved photocatalytic performance of α-SW/UNCN was owing to the construction of n-p-n type double Z-scheme heterojunction which enhanced carries separation. This work will provide a method for preparing novel and efficiency ternary composite catalyst for antibiotic contaminant degradation and H 2 production. [ABSTRACT FROM AUTHOR]

In this study, a commercial rutile titanium dioxide (R-TiO 2) with a particle size of 200–300 nm was used as a carrier to prepare R-TiO 2 /n-TiO 2 photocatalysts through wet co-grinding in a stirred grinder, along with commercial TiO 2 (n-TiO 2). The structure of R-TiO 2 /n-TiO 2 , its photocatalytic degradation performance towards methyl orange, and the enhancement mechanism were investigated. The results demonstrated that under the optimized conditions of grinding time and n-TiO 2 loading ratio, the prepared R-TiO 2 /n-TiO 2 composite (with a n-TiO 2 ratio of 30%) exhibited excellent photocatalytic degradation and recyclability. After 30 min of UV irradiation, the removal rate of methyl orange was 99%, which was comparable to that of pure n-TiO 2 (degradation rate of 99.5%). The degradation rate of methyl orange using R-TiO 2 /n-TiO 2 was 4.5 times higher than that of an equivalent proportion of n-TiO 2 , and the degradation performance remained nearly unchanged after five cycles of recycling. R-TiO 2 /n-TiO 2 exhibits features such as effective dispersal and even distribution of n-TiO 2 onto the surface of R-TiO 2 , coupled with the establishment of chemical bonding at the interface between the two constituents. The existence of R-TiO 2 improved the dispersion of n-TiO 2 and promoted the formation of an interfacial anatase/rutile heterophase junction, which are intrinsic mechanisms for enhancing the efficiency of TiO 2 photocatalysis and achieving a reduction in the application process. • R-TiO 2 /n-TiO 2 composite photocatalysts exhibited excellent degradation performance. • R-TiO 2 /n-TiO 2 achieved 4.5 times faster degradation of methyl orange compared to n-TiO 2. • Effective dispersion, interfacial bonding, and heterophase junction formation enhanced the photocatalytic efficiency. [ABSTRACT FROM AUTHOR]

Various features can benefit the sintered NdFeB material modeling process, as they provide more dimensional information related to the target and make the model more accurate. In this work, by introducing composition and process features as input, we successfully built a sintered NdFeB performance prediction model by comparing different machine learning models with good generalization capability, high accuracy, and sound interpretation compared to previously published work. In addition, using the Shapley additive interpretation (SHAP) method, the unexplainable problem of ML models is solved by evaluating the contribution of the features in the regression model to the results. The intuitive SHAP value plots showed the complex relationship between input variables and magnet performance. Finally, we used the above machine learning model to complete the process framework for evaluating the performance of sintered NdFeB materials. Our work is expected to accelerate performance screening and material development of sintered NdFeB. [Display omitted] • A machine learning model has been developed to predict the remanence and coercivity properties of sintered NdFeB. • The developed models demonstrate high accuracy and generalization on the respective test sets. • Interpretation of machine learning models using SHAP analysis. • The machine learning model is utilized to propose a material design framework for sintered NdFeB. [ABSTRACT FROM AUTHOR]

Precipitation strengthening, which requires controlling the type, size, and distribution of precipitation particles, is attractive for high-entropy alloys (HEAs). Here, we demonstrate an effective approach for the secondary phase precipitation of La 0.005 Al 0.17 FeCoCrNiMn HEAs by rapid solidification and aging treatment. The supersaturated La and Al atoms were present in the face-centered-cubic (FCC) matrix via rapid solidification, which prevented the formation of large size secondary phases. The homogenization heat treatment promoted the disappearing of the dendritic structure and the precipitation of the LaAl 1.06 Ni 3.94 phase. Subsequently, two types of precipitated phases were observed during the aging treatment: (1) the Cr-rich M 23 C 6 phase, which was distributed along the grain boundary and coherent with the FCC matrix; and (2) the Cr-rich σ phase, which connected with the LaAl 1.06 Ni 3.94 phase via the periodic stacking faults between them. The forming abilities of the ternary La-Al-Ni interphase have been systematically described based on the Miedema's and Toop's model. The microhardness reached 156 HV and the tension strength increased from 343 MPa to 437 MPa after the aging treatment. This work provides a fundamental research basis for controlling the precipitation strengthening of HEAs. • The large size AlNi and RENi phases were avoided via rapid solidification when RE or Al added into the FeCoCrNiMn HEAs. • The forming ability of LaAl 1.06 Ni 3.94 phase has been systematically described via the Miedema's and Toop's model. • The crystallographic orientation relationships of the precipitated phases for strengthening were clearly determined. • Rapid solidification method is an efficient way to the application of RE or Al element in the FeCoCrNiMn HEAs. [ABSTRACT FROM AUTHOR]

MoSi 2 has a low density, high conductivity, and anti-fluorine structure. Therefore, we prepared MoSi 2 -modified LiNi 0.6 Co 0.1 Mn 0.3 O 2 (NCM613) materials by a solid-state method using the precursors of MoSi 2 and NCM613. Analysis using XRD, HRTEM, SEM and XPS reveals that a small amount of Mo from MoSi 2 was doped into the NCM613 lattice, and the rest MoSi 2 was coated on the material surface. DFT calculations show that Mo atom doping preferentially replaces Ni sites in the NCM613 transition metal layer to form more Ni2+. The capacity retention of the best modified sample NCM-0.5MoSi 2 is 74.1% (from 174.0 to 129.0 mAh·g−1) after 300 cycles at 1 C, while the pristine material NCM-0 is only 49.6% (from 171.5 to 85.1 mAh·g−1). Furthermore, the lithium-ion diffusion coefficient of NCM-0.5MoSi 2 is 3.44 × 10−12 cm2·s−1, higher than 2.73 × 10−12 cm2·s−1 of NCM-0. Improved electrochemistry results from Mo doping and MoSi 2 coating, where Mo doping expands the lattice parameters of NCM613 and MoSi 2 coating protects NCM613 from hydrofluoric acid (HF) corrosion. This work achieves the dual effect of Mo doping and MoSi 2 coating through the modifier MoSi 2 , and provides a reference scheme for the improvement of other cathode materials. [Display omitted] • MoSi 2 -modified NCM613 material was prepared by solid-state method. • Dual effects of Mo doping and MoSi 2 coating achieved by modifier MoSi 2. • XPS combined with DFT further studied the mechanism of Mo doping. • MoSi 2 coating plays a dual role of high conductivity and anti-fluorine structure. • The capacity retention of NCM-0.5MoSi 2 is 74.1% after 300 cycles at 1 C. [ABSTRACT FROM AUTHOR]

Fe-rich Sm 2 Co 17 -type magnets have many essential applications prospects in high-temperature operation environments. However, the formation of complete cellular microstructure becomes increasingly difficult when the Fe content of Sm 2 Co 17 -type magnets exceeds 20 wt%. Herein, the phase stability of 1:7 H phase and its effect on the precipitation of the 1:5 H precipitates in Fe-rich Sm 2 Co 17 -type magnets are investigated. The results confirm that the stability of the 1:7 H phase decreases with the increasing of Fe content for the solution-treated magnets. Not only 2:17 R phase but also a lot of 2:17 R′ phase is found in solution-treated magnets when the Fe content exceeds 22 wt%. As the Fe content increases, the density of initial defects decreases for the growth of 2:17 R nanotwins in the solution-treated magnets. Furthermore, the segregation of Cu in the defects-aggregated cell boundaries weakened gradually. Consequently, the nucleation and precipitation of cell boundary precipitates is difficult, and the cellular microstructure becomes incomplete and coarse when the Fe content is above 22 wt%. The present work may provide a further insight for understanding the evolution of cellular microstructure depending on the phase decomposition behavior in Fe-rich Sm 2 Co 17 -type magnets. • Various 2:17 R′ phases were found in solution-treated Sm 2 Co 17 -type magnet when the Fe content is above 22 wt%. • The ordering of 2:17 R phase during the solution treatment is not conducive to the segregation of elements. • According to XRD Rietveld analysis, the stability of 1:7 H phase decreases with the increase of Fe contents for the solution-treated magnet. [ABSTRACT FROM AUTHOR]

Nickel-rich ternary material faces up with the performance degradation problem associated with its poor structural stability and interfacial side reactions with the electrolyte. Herein, boron and nitrogen co-modified LiNi 0.6 Co 0.1 Mn 0.3 O 2 material was synthesized, aiming at studying the effect on the crystal structure, electronic conductivity and the electrochemical performance. It is interesting to find out that the rate performance and the cycle stability of the B&N co-modified materials are greatly associated with the ratio of B/N. The optimal sample NCM/B4N4 has initial specific discharge capacity 198.4 mAh g−1, the retention of 81.3% after 200 cycles (1 C) as well as the electronic conductivity of 5.00 × 10−4 S/cm, against the pristine NCM (194.0 mAh g−1, 56.7%, 1.22 ×10−4 S/cm). Moreover, the discharge capacity of the modified sample is improved obviously at high rate (5 C). TEM and XPS show that boron and nitrogen were successfully doped into the surface of the materials. Compared the PXRD patterns after 300 cycles and in situ XRD tests, it is found that the boron and nitrogen co-modification can inhibit the irreversible phase transition. DFT calculations disclose that Li layer thickness of the B&N co-doped sample is larger than that in individual B doped sample and the pristine material. GITT test confirms the higher lithium ions diffusion rate of NCM/B4N4. This work suggests that Nitrogen-doping can improve the electronic conductivity of Boron-doped material, consequently facilitating the Li ion diffusion of nickel-rich cathode materials. [Display omitted] • A cheap and convenient modification method of ternary material is proposed. • Nitrogen doping eliminates the effect of B 2 O 3 coating on initial capacity reduced. • B and N co-doping enhance electrochemical properties and electrical conductivity. • B&N co-modification can inhibit the irreversible phase transition of H2 to H3. • DFT calculations disclose that B&N co-dopants make Li-layer thickness enlarged. [ABSTRACT FROM AUTHOR]

The Pr 80 Al 20 (at%) alloy was diffused into the dual-main-phase Ce magnets (Ce/TRE = 40 wt.%, TRE: total rare earth) with different diffusion time by grain boundary diffusion process (GBDP). The magnetic property and the microstructure of a series of magnets with different diffusion time were investigated. The coercivity gradually increased as the diffusion time increased, while the remanence remained basically constant. The improvement of coercivity originated from the synergistic contribution of modified grain boundaries with decoupling effect and Ce-rich main phase containing Pr with improved magnetocrystalline anisotropy. The percentage of the irreversible portion and the nucleation field of the reverse domain calculated from recoil loops curves further confirmed that the diffusion of Pr 80 Al 20 alloy enhanced the coercivity. The enhanced anisotropy of the Ce-rich grains compensates for the decay of the remanence carried by the diffusion-induced increase in the nonmagnetic grain boundary phase, which ultimately results in the remanence remaining essentially constant. The above phenomena further broaden the room-temperature applications of dual-main-phase magnets with high Ce content without heavy rare-earth grain boundary diffusion. • Dual-main-phase magnets with high Ce content were diffused with light rare earth Pr-Al alloy. • Pr element mapping contrast clearly indicated sufficient diffusion inside the magnet. • Small amounts of Pr entered into the Ce-rich main phase grains to improve magnetocrystalline anisotropy. • Synchronous enhancement mechanism in coercivity and maximum energy product of the magnets was revealed. [ABSTRACT FROM AUTHOR]

The fabrication of Zn-based materials by laser powder bed fusion (LPBF) has been proved to be feasible. In this work, high relative density (98.10 %) of LPBF pure Zn samples were successfully obtained by optimizing the process parameters at low power (30–60 W). The microstructural formation mechanism and evolution of LPBF pure Zn under different power were investigated. With the increase of power, the recrystallization during the printing process became more completely, resulting in the increase of equiaxed grains integral number of the sample. The microhardness of the samples increases with the increase of the power, but the tribological properties change unobvious and the coefficient of friction of LPBF pure Zn in SBF solution is about 0.56–0.57. The electrochemical test manifests that, with the increase of power, the electrochemical corrosion rate of LPBF pure Zn increased, and the corresponding corrosion resistance decreased. • The high relative density samples of LPBF pure Zn were fabricated at low power and low scanning speed. • The formation mechanism and evolution of the microstructure of LPBF pure Zn were described. • The relationships among process parameters, microstructure, tribological properties and electrochemical properties were discussed. [ABSTRACT FROM AUTHOR]

SmFe 12 -based magnets have attracted considerable attention because of their high intrinsic magnetic properties. The metastable ThMn 12 -type SmFe phase can be easily decomposed into the α-Fe phase during heat treatment process. The nanocomposite theory of soft and hard magnetic phases is used to improve the magnetic properties of SmFe 12 -based magnets. At present, it is difficult to obtain strong exchange coupling in SmFe 12 /α-Fe nanocomposite magnets prepared by melt spinning or melt spinning followed by isothermal heat treatment. This study proposes a SmFe 12 /α-Fe nanocomposite magnet with a maximum energy product of 84.5 kJ/m3 by melt spinning followed by rapid thermal processing (RTP). The effects of RTP time on the phase composition, microstructure, and exchange coupling of the magnets were systematically studied. The results showed that a suitable RTP time benefitted the formation of fine and uniform 1:12 phase grains in the magnet. Henkel curves, magnetic domains and quantitative analysis based on the exchange coupling volume were employed to study the exchange coupling of the magnets, which indicated that the enhanced hard/hard-exchange coupling strength originating from the uniform and fine hard magnetic 1:12 phase grains is the main reason for the improvement in the overall exchange coupling strength. We believe this study provides a new technology for preparing high-performance SmFe 12 /α-Fe nanocomposite magnets with a high exchange coupling strength. [Display omitted] • By rapid thermal processing, a SmFe 12 /α-Fe nanocomposite magnet with the (BH) max of 84.5 kJ/m3 was prepared. • Rapid thermal processing improved exchange coupling within SmFe 12 /α-Fe nanocomposite magnets. • The enhanced interaction between the grains of hard magnetic phase is the main reason for the enhanced exchange coupling. [ABSTRACT FROM AUTHOR]

Titanium (Ti) and its alloys have great application potential. However, their relatively poor surface hardness, wear resistance, corrosion resistance, and biological activity greatly limit their effectiveness in practical applications. As a surface treatment method, the micro-arc oxidation (MAO) process has attracted much attention because it does not require expensive production equipment and is simple to operate. This paper discussed and summarized the mechanism of micro-arc oxidation and some classic models, which require development to provide better understanding and guidance for future research. Subsequently, the influencing factors of the formation of the micro-arc oxidation coating during micro-arc oxidation process were analyzed in detail. In addition, common applications of micro-arc oxidation coatings, including biomedical applications, wear resistance, corrosion resistance properties, and decoration, were summarized independently. Finally, existing problems and future prospects of the titanium alloy micro-arc oxidation process were discussed to facilitate the wide application of titanium alloy MAO process. [ABSTRACT FROM AUTHOR]

Grain refinement is the effective path to simultaneous enhancing both strength and toughness of the metal materials. Here we reported that, a super grain refinement effect has been acquired in the as-cast FeCoCrNiMn high entropy alloy via adding into 0.19 wt% B. The grain size distribution has been mainly concentrated below 150 µm and the average grain size has been refined from 3903 µm to 80 µm after B adding. The electron microscopy characterizations and relevant model calculations indicates that the B can form Cr 2 B phase which can be used as a high-efficiency nucleating agent and significantly refine the grain of the high entropy alloy. Meanwhile, the orientation relationships between the Cr 2 B phase and the HEA matrix have been confirmed. • After 0.19 wt% B adding into the FeCoCrNiMn high entropy, the grains have refined significantly due to the formation of Cr 2 B phase. • The fine equiaxed grains have been instead of the typical three grain zones and the average grain size approximated 1/50 of the original size. • In addition, the orientation relationships between Cr 2 B phase and the HEA matrix are {121}Cr 2 B//{111} matrix , < 01 2 ¯ > Cr 2 B / / < 2 ¯ 20 > matrix . [ABSTRACT FROM AUTHOR]

In this study, we investigated the effects of magnetic interactions within Nd-Fe-B magnets on first-order reversal curve (FORC) and the origin of negative regions in FORC diagram. Magnetostatic interaction causes the FORC diagram pattern to expand along the H u axis, especially in the direction of positive half-axis of H u. And the negative regions will tend to be embedded in the positive regions when magnetostatic interaction is not negligible. The origin of the negative peaks is the difference of the onset of magnetization and the subsequent magnetization process of adjacent FORCs caused by the different and complex stray fields within magnets at the beginning of the FORCs. Besides, the origin of the positive peaks is analyzed in detail as well. • The detailed effects of magnetic interactions within Nd-Fe-B magnets on their FORC are studied. • The origin of the negative region in the FORC diagram from a microscopic perspective is revealed. • Magnetostatic interaction has a significant impact on the relative position distribution of positive and negative regions. [ABSTRACT FROM AUTHOR]

Hybrid supercapacitors, inheriting the merits from supercapacitors and batteries, exhibit promise in energy storage technologies. However, they are bottlenecked by the sluggish diffusion, low mass loading and inadequate energy density. Herein, three-dimensional vertical orientation graphene-polypyrrole thick electrode (PPy@3DVAG) with vertically-aligned channels and three-dimensional conductive networks prepared via in-situ gas phase polymerization is proposed for high-energy-power zinc-ion hybrid supercapacitors to efficiently mitigate these issues. Based on the "dual-ion" storage mechanism, and associated with the multiple synergy of short mass/charge transfer pathway, fast kinetics and enhanced electroactivity endowed by the structurally engineering of thick electrode, even at the high active mass-loading (8.4 mg cm-2), the Zn-based hybrid energy devices with PPy@ 3DVAG-70 as cathode electrode exhibits intriguing capacitive performances, including exceptional high areal capacitance of 927 mF cm-2, good rate performance (53% at current density of 15 mA cm-2) and excellent areal energy/power density of 360.4 μWh cm-2 and 10.125 mW cm-2. The presented results highlight the facile and efficient approach for structural engineering the active cathode material, significantly contributing to the rapid development of eco-friendly and scalable Zn-based hybrid energy devices. • Three-dimensional vertical-orientation graphene-polypyrrole electrode is constructed. • High areal capacitance and excellent areal energy/power density are obtained. • Zn2+ ions storage of polypyrrole is realized to be a "dual-ion" storage mechanism. [ABSTRACT FROM AUTHOR]

Perovskite-phase (1 − x)Ba 0.5 Bi 0.5 FeO 3 − x Gd 2 O 3 ceramics with negative temperature coefficient (NTC) were synthesized by solid-state reaction. X-ray diffraction (XRD) measurements showed that all samples exhibited a tetragonal perovskite structure. In addition, all samples showed a typical NTC effect; their room resistivity ρ 25 and thermal constant B 25/75 were regulated by the Gd 2 O 3 doping content, and varied in the 4.70 × 105–4.72 × 106 Ω cm and 5573–6697 K ranges, respectively. In situ X-ray photoelectron spectroscopy (XPS) elucidated the conduction mechanism of Ba 0.5 Bi 0.5 FeO 3 -based ceramics was the electron hopping type, and the source of NTC effect was the change in the content of different valence ion pairs and the increase in electronic mobility with increasing temperature. Impedance analysis showed that the samples were electrically inhomogeneous, and their grain boundary resistance was higher than the grain resistance. The corresponding relaxation process might originate from the release of space charge and the ionization of oxygen vacancies. • Pure and Gd 2 O 3 doped BBF ceramics all have typical NTC effect. • The addition of Gd 2 O 3 can regulate the resistivity and B values of BBF ceramic. • In situ XPS revealed the source of NTC effect in BBF based ceramics. • Both grain and grain boundary contribute to the NTC characteristic of samples. • The relaxation process is related to the space charge and oxygen vacancy. [ABSTRACT FROM AUTHOR]

The NiCo 2 O 4 anode has high theoretical specific capacity for Li/Na-ion batteries, but the low conductivity and volume expansion during lithiation and delithiation lead to severe capacity fading. In this study, a porous bead-like NiCo 2 O 4 /carbon composite nanofiber with a metal-organic frameworks (MOFs) structure is prepared by tuning the ratio of polyacrylonitrile (PAN) during the electrospinning process. The MOF-derived NiCo 2 O 4 particles were firmly anchored on highly conductive carbon nanofibers, generating the sturdy construction and large specific surface area (169.7 m2/g) of NCO/C-12. Owing to these structural merits, more active sites are provided with accelerated electron/Li-ion transport upon cycling, and consequently the NCO/C-12 delivered a promoted cycling stability and synergistically enhanced rate performance. The reversible discharge capacity of 1125 mAh/g after 200 cycles and excellent rate performance of 695 mAh/g at 1.5 A/g are presented. And the NCO/C-12 electrode still kept its morphology and excellent structural stability without significant volume expansion or pulverization even after 200 cycles. When serving as anode materials for sodium-ion batteries (SIBs), the electrode also exhibited excellent cycling and rate performance. [Display omitted] • High specific surface area with robust pores conductive of MOFs structure composite nanofibers are prepared. • Superior discharge/charge capacities after 200 cycles and excellent rate performance are presented. • The NCO/C-12 as anodes for sodium-ion batteries (SIBs) are also exhibited excellent cycling and rate performance. [ABSTRACT FROM AUTHOR]

Body-centered cubic (BCC) medium-entropy alloys (MEAs) are characterized by high strength, low ductility and often high density due to containing much refractory elements. In this paper, a series of BCC Ti-Al-Nb-Zr medium-entropy alloys were constructed by adding different contents of Al to Ti 67 Nb 16 Zr 17 base alloy composed of α and β phases. It is shown that an enough addition of Al can depress the formation of α phase, resulting in single BCC structure. (Ti 67 Nb 16 Zr 17) 87 Al 13 alloy has the best comprehensive mechanical property as the strength-ductility trade-off is well overcome. Its specific strength is up to 230 MPa g−1 cm3 and its elongation is also as high as 18.5% in the as-cast state, better than most existing medium- and high-entropy alloy. It is revealed that abundant nanoscale chemical short-range order (CSRO) in the matrix phase plays an important role in the mechanical response of this alloy. • Addition of a certain amount of Al to some Ti-Nb-Zr base alloy results in single BCC phase with CSRO. • As-cast (Ti 67 Nb 16 Zr 17) 87 Al 13 alloy has very high specific strength and good elongation. • As-cast (Ti 67 Nb 16 Zr 17) 87 Al 13 alloy has superior mechanical property to most existing M/HEAs. • CSRO plays a dominant role in the mechanical behavior of (Ti 67 Nb 16 Zr 17) 87 Al 13 alloy. [ABSTRACT FROM AUTHOR]

In this work, the wide stacking faults (SFs) were introduced into high-purity Mg through large plastic deformation or annealing at the same time as adjusting the grain size, and the combined effects of wide SFs and grain size on the mechanical properties and corrosion resistance of high-purity Mg were clarified. It is found that the symmetrical rotary swaging can significantly refine the Mg grain and eliminate the wide SFs produced during the warm extrusion process, while the annealing can introduce the wide SFs with much higher density into the coarsened grains again. The grain refinement derived from rotary swaging after warm extrusion results in increased mechanical strength and corrosion resistance. The high-density wide SFs formed during annealing can improve the strength of high-purity Mg to more than 210 MPa, which is comparable to that of some Mg alloy. Meanwhile, the substantial coarsened grain only leads to slightly lowered corrosion resistance because the high-density SFs can delay the corrosion process. These findings provide novel approaches for achieving the desired mechanical properties and corrosion resistance of high-purity Mg, which can catapult its application in specific areas forward. • The high-density wide SFs were introduced into high-purity Mg with a specific process. • The SFs help the achievement of high strength and good ductility for high-purity Mg. • Grain size is more decisive for corrosion resistance of high-purity Mg than SFs. [ABSTRACT FROM AUTHOR]

Due to the difficulty in controlling thermodynamics and kinetics of the growth for branched bimetallic metal alloy nanocrystals in a solution system, understanding the growth mechanisms of this class of nanostructures is critical for their shape-controlled synthesis. Herein, we report an approach to control over shape of branched PtNi alloy nanocrystals by tuning the molar ratio of Pt to Ni in an oleyamine solution. The detailed analyses confirmed that the morphologies of PtNi alloy nanocrystals evolve from dendrites (less than 5 at% Ni) to multipods (5–10 at% Ni) to star shapes (10–20 at% Ni) and finally to polyhedrons (100 at% Ni) as the nickel content in PtNi alloy nanocrystals increase. During the morphology evolution, the growth mechanism changes from oriented attachment growth to a new mechanism combining oriented attachment and anisotropic overgrowth, then to kinetically controlled overgrowth and finally to thermodynamic control growth. More importantly, we find that the growth of branched PtNi alloy nanocrystals is always along the [220] direction, and the growth direction determines the number of branches in nanocrystals. Electrochemical results show that highly branched PtNi alloy nanocrystals exhibit significantly enhanced electrocatalytic activity and durability compared with commercial Pt catalysts. These in-depth findings will provide new hints to precisely control synthesis of highly branched PtNi nanocrystals. • The shape of branched PtNi alloy nanocrystals are tuned by adjusting atom ratio of Pt to Ni precursor. • The presence of nickel in the Pt4+-oleylamine system has a strong influence on Pt reduction kinetics. • The growth of the branched PtNi alloy nanocrystals is always along the (220) direction. • The branched PtNi alloy catalysts exhibit a high MOR activity compared to commercial Pt/C catalysts. [ABSTRACT FROM AUTHOR]

Composite materials based on reduced graphene oxide decorated with cuprous telluride nanoparticles (Cu 2 Te NPs@rGO) were fabricated using a facilitated two-step method. A back-contact layer was formed using a spin-coating method for cadmium telluride (CdTe) solar cells. This research is aimed to improve the photovoltaic performance of a device containing Cu 2 Te NPs@rGO/Au back contacts. Cu 2 Te NPs, as the active copper diffusion source, dope and passivate the interfaces and grain boundaries of CdTe to form the p+-layer, which can reduce the recombination centers and back-contact barrier height. Simultaneously, the reduced graphene oxide (rGO), as a buffer and carrier transport layer, prevents excessive copper diffusion during the annealing process and improves the hole collection capacity. The p-type layer formed by the rGO contact with the Au film enhances hole transport and facilitates a low-resistance contact formation, forming a quasi-ohmic contact, and increases the open-circuit voltage and short-circuit current density. Cu 2 Te NPs@rGO/Au back contacts significantly improved the photovoltaic performance (E ff : 16.5%, V oc : 830 mV, J sc : 27.13 mA/cm2, fill factor: 73.3%, area: 0.24 cm2). The composites retain properties of Cu 2 Te NPs and rGO. Their multifunctional properties reveal the potential of Cu 2 Te NPs@rGO as the back contact and broaden the application of graphene-based composites in photovoltaic devices. Additionaly, the preparation of graphene-based composites and their application as back contact is simple and convenient. • The Cu 2 Te NPs@rGO composites is synthesized by a facilitated two-step method. • The Cu 2 Te NPs@rGO composites is firstly used as the back contact for CdTe solar cells. • Cu 2 Te NPs can effectively dope the CdTe layer, and rGO/Au can reduce the barrier height. • A quasi-ohmic contact is formed by the Cu 2 Te NPs@rGO composites. • A significant enhanced performance (e.g., Eff: 16.5%, V oc : 830 mV, J sc : 27.13 mA/cm2, FF: 73.3%, area: 0.24 cm2) is achieved for CdTe solar cells. [ABSTRACT FROM AUTHOR]

Recently, an innovative process chain has been investigated and proposed, using laser-based directed energy deposition technology to produce pre-forms for forging. The advantage of this technology is to get high-performance near-formed parts at a low cost, compared traditional processing. Clarifying the hot workability and the microstructural evolution of as-deposited samples is the key to obtaining high performance parts. In present work, the plastic behaviors and dynamic recrystallization mechanisms of as-deposited nickel-based superalloy are studied. The compression curves are corrected by eliminating adiabatic heating and friction effect. And then the hot deformation activation energy and the constitutive equation of as-deposited sample are obtained. Compared to the wrought Inconel 625, as-deposited Inconel 625 has lower hot deformation activation energy (466.511 kJ/mol). The peak stress gradually decreases, while the recrystallized grain volume fraction gradually increases when deformation temperature increases and strain rate decreases. The characterization results of TEM and EBSD show that the discontinuous dynamic recrystallization mechanism nucleating by the bowing of grain boundaries occupies an absolute dominant position. In addition, combined with the microstructural evolution and hot processing map, the best hot working conditions of as-deposited Inconel 625 are obtained (deformation temperature: 1050–1150 ℃, strain rate: 0.001–0.01 s−1). • Hot compression stress-strain curves of Inconel 625 fabricated by L -DED were corrected by eliminating the influences of adiabatic heating. • The constitutive equation and hot processing map of as-deposited Inconel 625 were established. • The dynamic recrystallization mechanism of Inconel 625 fabricated by L -DED during hot deformation process was discussed. [ABSTRACT FROM AUTHOR]

An innovative self-powered ultraviolet photodetector based on ZnO/CuBO 2 core-shell nanorod arrays was fabricated using cost-efficient and scalable preparation technologies, including a chemical hydrothermal method and an impregnation technique. The ZnO/CuBO 2 core-shell heterostructure exhibits significant diode behavior with a rectification ratio approaching 7016 at± 1 V because of the type-II band alignment formed at the heterojunction interface, acquiring a maximum responsivity of 165 mA /W1 with an external quantum efficiency of 55.3% (370 nm, 65 mW cm−2) and specific detectivity (4.13 ×1012 cm Hz1/2 W−1) under zero bias. Simultaneously, by applying an external bias to adjust the photovoltaic and pyroelectric effects and delving into the operating mechanisms, the photodetector based on the ZnO/CuBO 2 heterostructure achieves enhanced performance. The decay time has been shortened, and the responsivity has reached up to 38.82 A W−1 (apparent quantum efficiency ~ 13,010%) at − 2.5 V. Moreover, the effects of the power density on the photocurrent response and temperature induced by the photovoltaic-pyroelectric effect are discussed. This study reveals the potential of CuBO 2 (one of the Cu-delafossite families) as a hole transport layer in optoelectronic devices, broadens the application prospects of core-shell nanorod arrays based on the photovoltaic-pyroelectric effect, and provides a direction for modulating the performance of such devices. • CuBO 2 , as a p-type layer of copper delafossite, was firstly used to covered ZnO nanorods forming a core-shell structure. • The facile, convenient and low-cost processes were demonstrated to fabricate original self-powered ZnO NRs/CuBO 2 core-shell heterojunctions. • The performance of the photodetector has been enhanced by modulating photovoltaic and pyroelectric effects. • The curves of output current I pyr+pho , proportion of I pyr and temperature varying with the incident light power densities were fitted with the power-law I&T = AP α. • Significant excellent performance, e.g., R=165 mA W−1 @0 V, 38.82 A W−1 @-2.5 V (370 nm, 65 mW cm−2), D* λ =4.13×1012 cm Hz1/2 W−1, RR=7016 at±1 V, was achieved for self-powered ultraviolet photodetectors with ZnO NRs/CuBO 2 core-shell sturcture. [ABSTRACT FROM AUTHOR]

The cathode material for lithium-ion batteries, LiCoO 2 (LCO), is suffered from the structural damage and rapid performance degradation at high voltage. In this article, a hydrolysis-calcination method was explored to modify the single-crystal LCO particles with Ti&F co-modification, aiming at strengthening the structural stability through decreasing the energy barrier of lithium ion diffusion. Evaluated at high voltage (3.0–4.55 V), the optimal sample LCO-TF2 has the initial discharge capacity of 199.3 mAh g−1 and capacity retention rate of 75% after 100 cycles at 1 C and 45 °C, significantly higher than that of the pristine sample (192.8 mAh g−1 and 35%). Characterized by XRD, TEM, XPS, etc., it is illustrated that the Ti&F co-modified sample LCO-TF2 has the rock-salt phase on its surface besides the layered structure inside. GITT results indicate that Li+ diffusion coefficients of LCO-TF2 are more than twice times of those of LCO under the voltage range of 4.0–4.55 V. The in-situ XRD tests reflect that during the charge-discharge cycle the crystal structure variation of LCO-TF2 is suppressed during Li+ extraction and insertion. Further, DFT calculations disclose that with the co-modification of Ti and F the surface film of LiCoO 2 possesses lower energy barrier of Li-ion diffusion. These results would provide useful guidance on improving electrochemical performance of LiCoO 2 at high cut-off voltage. Ti&F co-modification enhanced the structure stability of LiCoO 2 , reduced the energy barrier of Li-ion diffusion, thus significantly improved the high voltage performance. [Display omitted] • A hydrolysis-calcination method using (NH4)2TiF6 and carbamide was developed to modify LiCoO 2. • Ti&F co-modified sample (LCO-TF2) showed higher capacity and retention rate at 3.0–4.55 V. • The surface film of LCO-TF2 has the rock-salt phase. • DFT calculations disclosed that Ti&F co-modification can significantly decrease the energy barrier of Li-ion diffusion. [ABSTRACT FROM AUTHOR]

Semiconductor photocatalysts, especially semiconductor heterojunctions, have great development potential in the field of photocatalysis. SnO 2 /g-C 3 N 4 heterojunction has shown excellent photocatalytic performance rather than single SnO 2 or g-C 3 N 4 , particularly for visible-light-driven photocatalysis. In this review, the synthesis methods of SnO 2 /g-C 3 N 4 heterojunction are summarized. Then, the modification strategies of morphology control, defect introduction and multiple structural optimization strategies are highlighted. Morever, the possible mechanisms and applications in environment remediation and energy conversion of SnO 2 /g-C 3 N 4 heterojunction are discussed. Finally, the challenges and perspectives of SnO 2 /g-C 3 N 4 heterojunction are also proposed. [ABSTRACT FROM AUTHOR]

• A short-range grain boundary diffusion process is proposed to improve the uniformity of coercivity. • The disappearance of α-Fe phase and the formation of intergranular phases contribute to huge improvement of coercivity. • Anisotropic hot deformed Nd-Fe-B magnets with high performance were fabricated. • The metallurgical behavior of elements and intergranular phase evolution are investigated. [Display omitted] For usual grain boundary diffusion, the diffused source infiltrates into the magnet from the surface, and a long diffusion distance leads to non-uniform distribution of elements, which seriously restricts the improvement of properties and reduces the uniformity of coercivity. In this work, based on nanocomposite Nd-Fe-B ribbon, a short-range grain boundary diffusion (SRGBD) process is employed to improve coercivity, obtaining a high coercivity of 24.27 kOe in PrCuAl-diffused nanocomposite powder, increasing by 233.0% comparing to the initial ribbon. By spark plasma sintering (SPS) technique, an isotropic magnet with high coercivity of 24.13 kOe is prepared, and meanwhile, good uniformity of coercivity is also achieved. The disappearance of the α-Fe phase and the formation of intergranular phases contribute to a huge improvement of coercivity. At last, with the help of the intergranular phase, established by SRGBD, anisotropic magnets are successfully prepared through hot deformation, which the optimum magnetic properties with H ci = 18.99 kOe, J r = 1.08 T, and (BH) max = 215 kJ/m3 can be achieved. [ABSTRACT FROM AUTHOR]

• The magnets diffused that the (BH)max is 40.39 MGOe, and Hcj increases by about 45.7% compared to the original magnets. • For XRD, there are marked characteristic peaks of REO and RE Oxyfluoride phases in diffused magnets. • The Ce-lean grains have better {001} orientation, in contrast, the Ce-rich grains have weaker orientation occurred along<001>direction. • The gradient distribution structure of the anisotropic field (GDSAF) leads to the lattice distortion, the grade of lattice distortion comes to increase with the magnetocrystalline anisotropy growing. The Ce-contained dual-main-phase magnets that the (BH) max is 40.39 MGOe, and H cj increases to 16.61 kOe get well magnetic properties by grain boundary diffusion. The H cj increases by about 45.7% compared to the sintered state magnets. The XRD shows that RE-O-F compounds are formed in the diffused surface, the characteristic peak is distinct respectively. The gradient distribution structure of the anisotropic field (GDSAF) appears in SEM due to diffusing. Compared with the original (Nd, Ce)-Fe-B grains, EBSD shows that the Exp. Densities (mud) in the direction of {002} of Ce 2 Fe 14 B main-phase keep better in diffused magnets. The texture of Ce 2 Fe 14 B main-phase is changed from ring-like to the ring, the max value of Exp. Densities (mud) in the direction of {002} in the pole figure gets tremendously improvement. According to the variation of orientation distribution, in terms of elements distribution, the large difference is that whether Tb atoms diffuse into RE 2 Fe 14 B main-phase forming GDSAF. [ABSTRACT FROM AUTHOR]

• The most outstanding electrochemical performance of the PBAs anodes are achieved. • The interstitial H 2 O could attenuate the electrostatic repulsion within multiple Li+ in the KxMn[Fe(CN) 6 ] y structure. • The new reaction pathway between Li+ and KxMn[Fe(CN) 6 ] y is proposed, involving the fracture and recombination of MnN bond. • The weaker MnN bond is more conducive to the reversible conversion reaction. Prussian blue analogues (PBAs) have garnered much attentions in energy fields due to their three-dimensional open framework and electrochemical tunability. Noticeably, PBAs are also deemed extremely attractive as anode materials for batteries by virtue of their abundant internal active sites. However, their unclear redox mechanisms at lower potential severely restricts PBAs anodes to realize stable cycling performances. In this work, low-cost KxMn[Fe(CN) 6 ] y □ 1−y ·nH 2 O with diverse H 2 O content and structure are harvested via controlling the crystallization rate. It is firstly discovered that the KxMn[Fe(CN) 6 ] y anodes undergoes multi-electron conversion reactions involving the fracture and recombination of Mn N bonds, while the stronger Fe C bond is preserved. Then, it is confirmed that weaker Mn N bond which need to be prepared at a faster crystallization rate is more conducive to the fast electrochemical kinetics of the reversible conversion paths. Accordingly, the K 0.09 Mn[Fe(CN) 6 ] 0.66 □ 0.34 ·3.40 H 2 O with higher H 2 O content and weaker Mn N bond achieve the best Li-storage performances, exhibiting a reversible capacity of 480 mAh g−1 at a high current density of 1 A g−1 and considerable cycling stability exceeding 1000 cycles. The results also suggest that interstitial H 2 O could be beneficial for the better cycling stability of the KxMn[Fe(CN) 6 ] y anodes. This work can provide new insights for the rational design of novel conversion anodes with high reversible capacity and superior cycling stability. [ABSTRACT FROM AUTHOR]

• Pure and Cr doped CCTO ceramics all have obvious NTC effect. • The addition of Cr 2 O 3 can regulate the resistivity and B values of CCTO ceramic. • The conductive mechanism of CCTO ceramics is the electron hopping. • Both grain and grain boundary contribute to the NTC characteristic of samples. • The relaxation behavior is due to the space charge and dipolar polarization. In the present work, CaCu 3- x Cr x Ti 4 O 12 (CCCTO, 0 ≤ x ≤ 1) ceramics were prepared by a solid-state reaction. The influence of Cr on the structure and electrical properties of the CCCTO ceramics was investigated in detail. X-ray diffractometry (XRD) revealed that all samplesʼ main phases were CaCu 3 Ti 4 O 12 (CCTO), but CuO and CaTiO 3 phases were also found. Cr doping suppressed the abnormal growth of grains, thus the grain size distribution became more uniform with the increase of Cr doping content. The resistance-temperature analysis revealed that all CCCTO ceramics had a noticeable Negative Temperature Coefficient (NTC) effect. The resistivity ρ 30 of the CCCTO ceramics decreased from 1.15 × 106 to 8.73 × 104 Ω cm with an increase in the value of x , along with a decrease in the thermal constant B from 6596 to 3267 K. It was also observed that both the grain and grain-boundary effects contributed to their NTC characteristics. The analysis revealed that the conductivity of the ceramics arose mainly from the electron hopping mechanism. All the samples showed an electrical relaxation behavior. The observations indicated that the structures and electrical properties of CCCTO ceramics could be attuned precisely by adjusting the concentration of the Cr 2 O 3 doping agent. [ABSTRACT FROM AUTHOR]

• Large electrostrictive response was obtained in modified BNT-based ceramics. • High-temperature and long-term stability was obtained. • The materials have great potential for actuator applications. In this study, we report lead-free Co/Sb-codoped (Bi 0.5 Na 0.5)TiO 3 -based ceramics with enhanced electrostrictive properties and high-temperature and long-term stability. The effect of Co/Sb codoping on the phase structure, electrical properties, and thermal stability of (Bi 0.5 Na 0.5)TiO 3 -based ceramics was studied. The Co/Sb codoping induced the phase transition from the coexisting rhombohedral (R) − tetragonal (T) phase to the single pseudocubic (Pc) symmetry and the disruption of the long-range ferroelectric order of the ceramics, yielding enhanced electrostrictive properties. A large electrostrictive response was obtained in the sample with 0.02 Co/Sb content, with electrostrictive coefficients Q 33 of 0.022–0.024 m4/C2 and electro-strains of 0.35–0.46% under different strengths of the electric field. The electrostrictive material exhibited temperature-insensitive and fatigue-free behavior after up to 105 cycles from room temperature to 120 °C, rendering it a promising material for high-temperature and long-term stability actuator applications. [ABSTRACT FROM AUTHOR]