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Bi 0.5 Na 0.5 TiO 3 -based ferroelectric ceramics have broad application prospects due to their excellent electrical properties and are considered to be one of the most promising functional materials to supersede lead-based materials. Here, 0.9Bi 0.5 Na 0.5 TiO 3 -0.1Bi 0.2 Sr 0.7 TiO 3 - x NaNbO 3 (BNT-BST- x NN) ternary lead-free ferroelectric ceramics were prepared, and the origin of their excellent dielectric properties was investigated in terms of phase boundary and domain structure. The introduction of NN led to a phase transition from the ferroelectric rhombohedral phase (R 3 c) to the relaxor tetragonal phase (P 4 bm), and the two phases coexisted in the BNT-BST- x NN ternary solid solution with x ranging from 0.06 to 0.2. Meanwhile, the macroscopic domain of BNT-BST was destroyed and replaced by highly active polar nano-regions (PNRs) of the P 4 bm phase, leading to an increase in local structural disorder and enhanced relaxor behavior. A dielectric constant (ε r) of ∼1765 (150 °C) with Δ ε / ε 150 °C less than 15 % over a broad range from 80 to 328 °C was achieved in the BNT-BST-0.15NN, and an excellent energy storage property (W rec = 3.3 J/cm3) was obtained under a low electric field (190 kV/cm). More specifically, the relationship among phase boundary, domain structure, and excellent electrical properties was achieved based on Rietveld refinements and the dielectric/ferroelectric characterizations. This work provides a deep insight into the phase evolution and its impact on the electrical properties of the BNT-based relaxor ferroelectrics. [ABSTRACT FROM AUTHOR]

Boron carbide ceramics are potentially ideal candidates for lightweight bulletproof armor, but their use is currently limited by their low fracture toughness. Recent experimental results have shown that sintered samples with high twin densities exhibit high fracture toughness, but the toughening mechanism and associated crack propagation process of nanotwinned boron carbide at the atomic scale remain a mystery. Reported here are molecular dynamics simulations with a reactive force field potential to investigate how nanoscale twins affect the fracture toughness of boron carbide ceramics. The results show that the strength disparity on either side of a twin boundary is the fundamental reason for the toughening effect; the twin boundary impedes crack propagation only when the crack moves to a region of higher fracture strength. The fracture toughness of nanotwinned boron carbide is greatly affected by the angle between the twin boundary and the prefabricated crack. At an angle of 120°, the twin boundary provides the maximum toughening effect, enhancing the toughness by 32.72%. Moreover, phase boundaries—another common structure in boron carbide ceramics—have no toughening effect. This study provides new insights into the design of boron carbide ceramics with high fracture toughness. [ABSTRACT FROM AUTHOR]

In the current study, the incorporation of Ba(Sn0.70Nb0.24)O3 (BSN) effectively modifies the phase boundary of the 0.8(Bi0.50Na0.50)TiO3‐0.2(Bi0.50K0.50)TiO3 (BNKT) lead‐free ceramic material, inducing enhanced electrostrain properties at room temperature, particularly results in a "bud‐like" strain profile without negative strain. A comprehensive investigation has been conducted into the microstructure, electrical properties, and electrostrain properties of the above‐mentioned ceramics. The addition of BSN was observed to be well incorporated into the BNKT crystal structure, forming a single perovskite structure according to the X‐ray diffraction pattern. With the increase in BSN solid solution content, the temperature at which the transition from ferroelectric to the relaxor phase occurs shifted from 88.1°C to beneath room temperature (30°C). Specifically, the BNKT‐0.0075BSN ceramic demonstrated a positive strain response of 0.459% along with a large signal piezoelectric coefficient (d33*) of 643 pm/V. Additionally, the strain hysteresis of the BNKT‐0.0175BSN ceramics was only about 3% at 120°C. These experimental findings suggest that BNKT‐xBSN ceramics could be strong contenders for actuators and sensors, presenting promising opportunities for lead‐free ceramic actuator applications. [ABSTRACT FROM AUTHOR]

Bismuth sodium titanate (BNT) ceramics exhibit outstanding strain responses but are unfavorable for application in high-sensitivity displacement actuators due to the large negative strain resulting from irreversible changes in their phase transition and domain structure. Here, (1−x)Bi0.50Na0.41K0.09TiO3–xNaNbO3 (BNKT−xNN) solid solutions were prepared to improve the strain properties through the strategy of modulating the phase boundary and domain structures. The introduction of sodium niobate could effectively regulate the relative content of the tetragonal (P4bm) and rhombohedral (R3c) phases in the phase boundary region. The ferroelectric-to-relaxor phase transition (TF−R) was reduced, and the ergodic relaxor (ER) state was nurtured at room temperature. Excellent zero-negative strain properties of S = 0.41% and d33* = 742 pm/V were achieved from the reversible transition between the ER and ferroelectric states under an applied electric field (x = 0.04). Additionally, understanding the domain states via piezoelectric force microscopy (PFM) and first-order reversal curve (FORC) revealed that the superior strain responses originated from the reversible inter-transformation of substable macrodomains and polar nanoregions (PNRs) in the phase boundary. This study provides new insight into the interplay between the evolution of phase boundaries and domain structures and the strain properties of BNT-based ceramics.

[Display omitted] Piezoelectric catalysis, which converts mechanical energy into chemical activity, has important applications in environmental remediation. However, the piezo-catalytic activity of various piezoelectric materials is limited by the weak piezoelectricity as well as the mismatched band-gap, leading to inefficient electron-hole pair generation and difficult carrier migration. Here, a simple strategy combining phase boundary and energy band structure modulation was innovatively proposed to enhance the piezo-catalytic activity of BaTiO 3 ferroelectric by Ce ions selecting different doping sites. Thanks to the coexistence of tetragonal (P 4 mm) and orthorhombic (Amm 2) phases effectively flattened the Gibbs free-energy and thus enhanced the piezoelectric activity, as well as suitable energy bandwidth facilitating the carrier migration were realized in the B-sites doped Ba(Ti 0.95 Ce 0.05)O 3. The degradation rate constant k of tetracycline (TC) was high to 30.56 × 10-3 min−1, which was 2.03 times higher than that of pure BaTiO 3 and superior to most representative lead-free perovskite piezoelectric materials. Theoretical calculations validated that the charge density and high O 2 and OH– adsorption energy on the Ba(Ti 0.95 Ce 0.05)O 3 surface promoted more efficient •O 2 – and •OH radicals conversion and bettered response to piezo-catalytic reaction. This work is important to design high-performance piezo-catalysts by synergistic regulation of phase boundary and energy band structure in perovskite materials for long-term antibiotic tetracycline removal. [ABSTRACT FROM AUTHOR]

Under high pressures, many crystalline metals undergo solid–solid phase transformations. In order to accurately model the behavior of materials under extreme loading conditions, it is essential to understand the kinetics of phase transition. Using molecular dynamics simulations, this work demonstrates the feasibility of characterizing the speeds of a moving phase boundary using atomistic simulations employing a suitable empirical potential for single-crystal magnesium. The model can provide temperature- and tensorial stress-dependent velocity of a moving phase boundary as a rate-limiting contribution to the kinetics of phase transformation in continuum codes. Results demonstrate that a nonlinear interaction exists between plasticity and phase transition, facilitating a jump in the velocity of a moving phase boundary, facilitated by activated plastic deformation mechanisms. [ABSTRACT FROM AUTHOR]

Rechargeable Zn‐air batteries (ZAB) represent a promising avenue for sustainable energy storage, boasting high energy density, cost‐effectiveness, scalability, and environmental friendliness. However, the sluggish redox kinetics and limited cycle life of bifunctional oxygen evolution/reduction (OER/ORR) electrocatalysts impede the further practical development of ZABs. In this study, homogenic boundary effect within α/β‐NiMoO4 is introduced as a superior electrocatalyst for ZAB. Through in situ poikilothermic X‐ray diffraction, X‐ray absorption spectroscopy, and theoretical investigations, the active Ni atoms exhibit more effective electron transfer at α/β‐NiMoO4 due to the homogenic boundary effect is unveiled. Furthermore, the presence of oxygen vacancies and lattice distortions at these boundaries significantly reduces the thermodynamic barrier of OER to a mere 0.46 V. Consequently, α/β‐NiMoO4 demonstrates a remarkably low overpotential of 270 mV at 10 mA cm−2 for the bottlenecked OER, along with prolonged durability (150 h) and a high specific capacity (745 mAh g−1 at 5 mA cm−2) for ZAB. This study underscores the efficacy of homogenic boundary effects in enhancing electrocatalytic activities, offering great promise for the advancement of sustainable energy systems. [ABSTRACT FROM AUTHOR]

After defining the fractional Λ -derivative, having all the prerequisites for corresponding to a differential, the fractional Λ -strain has already been established. Furthermore, only globally variational principles are allowed in the context of fractional analysis. Hence, balance laws, yielding the various field equations in Λ -fractional continuum mechanics, are derived, allowing corners in their fields. The basic balance laws of mass, linear and rotational momentum, and energy conservation with jump conditions are derived in the context of Λ -fractional analysis. [ABSTRACT FROM AUTHOR]

Temperature stability of electrocaloric effect (ECE) is a thorny problem in ferroelectrics (FE). A general method is to design ferroelectric-to-relaxor phase transition at a sacrifice of electrocaloric (EC) strength. The Pb(Yb1/2Nb1/2)O3 antiferroelectrics (AFE) + Pb(Mg1/3Nb2/3)O3 relaxors strategy designed in this work is effective to tackle this dilemma [(1 -- x)PYN--xPMN, x = 0.08-0.36]. PMN addition induces a successive phase transition and dual phase boundaries of ferrielectric (FIE)-nonergodic relaxor (NER) and NER-ergodic relaxor (ER), where ferroelectric polarization/strain and ECE reach a localmaximum. Thermally stable ΔT is unexpectedly achieved in FIE (x = 0.14) and NER (x = 0.24), except for a generality for ER state (x = 0.30). A dome-like variation trend is observed in x = 0.14 and 0.24 with a wide temperature span of ~60 and ~55 K (±15%ΔTmax). Notably, x = 0.24 NER possesses a large directlymeasured ΔTmax ~0.64 K simultaneously. Dielectric/ferroelectric properties clarify that two-stage transition of AFE rigid-order de-texture and dissociation of de-textured AFE domains into polar nano-entities accounts for thermal stability of ΔT as the alternation of ordered antipolar domains to disorder relaxors serves as a buffer to compensate for the thermal-shock enhanced random field. This work not only accounts for the underlying mechanism for thermal stability of ΔT at FIE and NER side for the first time in physics but also provides an exotic approach to seek for high-performance EC materials in practical applications. [ABSTRACT FROM AUTHOR]

In this study, we synthesized solid solutions of x Bi(Ni 1/2 Hf 1/2)O 3 -(1 − x)PbTiO 3 (x BNH-PT) with the aim of elucidating their phase boundary behaviors and the associated physical properties. A tetragonal (T) - pseudocubic (PC) phase boundary was confirmed at x = 0.38. For x = 0.36 and x = 0.37 with distinct tetragonal distortions, a spontaneous ferroelectric-relaxor transition was observed. The introduction of a T-PC phase boundary not only led to enhanced piezoelectric properties (d 33 = 456 pC/N, x = 0.39) but also effectively suppressed the spontaneous ferroelectric-relaxor transition. Detailed analysis revealed that the local structure of the initial state in 0.39BNH-0.61PT remained tetragonal. After poling, a long-range tetragonal phase was formed from the short-range tetragonal clusters, with the c/a value of ∼1.01. Our observations of frequency dispersion strongly suggest the presence of local inhomogeneities, resulting in distinct poling effects on the dielectric and elastic behaviors of the material. ● The onset of a T-PC phase boundary could enhance piezoelectric properties and suppress the spontaneous F-R transition. ● The poling field promoted the formation of a long-range T phase from the short-range T clusters in 0.39BNH-0.61PT. ● The presence of the local inhomogeneities gave different poling effects on the dielectric and elastic behaviors. [ABSTRACT FROM AUTHOR]

Boron carbide ceramics are potentially ideal candidates for lightweight bulletproof armor, but their use is currently limited by their low fracture toughness. Recent experimental results have shown that sintered samples with high twin densities exhibit high fracture toughness, but the toughening mechanism and associated crack propagation process of nanotwinned boron carbide at the atomic scale remain a mystery. Reported here are molecular dynamics simulations with a reactive force field potential to investigate how nanoscale twins affect the fracture toughness of boron carbide ceramics. The results show that the strength disparity on either side of a twin boundary is the fundamental reason for the toughening effect; the twin boundary impedes crack propagation only when the crack moves to a region of higher fracture strength. The fracture toughness of nanotwinned boron carbide is greatly affected by the angle between the twin boundary and the prefabricated crack. At an angle of 120°, the twin boundary provides the maximum toughening effect, enhancing the toughness by 32.72%. Moreover, phase boundaries—another common structure in boron carbide ceramics—have no toughening effect. This study provides new insights into the design of boron carbide ceramics with high fracture toughness.

Copyright of Bulletin of the Chinese Ceramic Society is the property of Bulletin of the Chinese Ceramic Society Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

BiFeO3–SrTiO3 (BF–ST) ceramics have been considered a novel class of lead‐free dielectric materials exhibiting notable dielectric constants and remarkable thermal stability. In this work, we fabricated a series of (1 − x)BF–xST (0.32 ≤ x ≤ 0.44) ceramics near the morphotropic phase boundary and comprehensively investigated their microstructure and electrical properties, which seeks to optimize the piezoelectric performance. As the ST content increases, a gradual reduction in the rhombohedral phase fraction is observed alongside a corresponding increase in the cubic phase fraction. Although x = 0.38, the maximum grain size of 5.66 μm is obtained, accompanied by a distinctive heterogeneous core–shell microstructure, which demonstrates a high remanent polarization of 51.2 μC/cm2 and a maximum d33 value of 72 pC/N. Furthermore, impedance spectroscopy analysis reveals the formation of a conductive core and a nonconductive shell within the sample. These findings highlight the potential of optimized BF–ST ceramics as promising alternatives to lead‐based piezoelectric materials, offering exceptional ferroelectric and piezoelectric properties. [ABSTRACT FROM AUTHOR]

The construction of phase boundaries is a well-known strategy to enhance the performances of ferroelectrics. In the present work, BiFeO 3 and BiInO 3 with attractive high Curie temperature of 830 °C and 600 °C were considered to reveal an unexplored phase boundary. (100- x)BiFeO 3 - x BiInO 3 (x = 10, 20, 30, 40, 41, 50, 60, and 80) films, with thicknesses of approximately 289 nm, were obtained through industrial-scalable sol-gel method on Pt/Ti/SiO 2 /Si substrates. Complete solid solution can form between BiFeO 3 and BiInO 3 , changing from rhombohedral to orthorhombic structure with the increase of BiInO 3 content. The macroscopic dielectric, ferroelectric and piezoelectric properties of the thin films were systematically studied to understand the effect of the solid solution, with its phase diagram being proposed. A phase boundary near 60BiFeO 3 –40BiInO 3 is formed with much superior polarization switch and piezoelectric response, of which the Curie temperature is as high as 470 °C. The results not only deepen the understanding of BiFeO 3 -based solid solutions, but also push forward potential applications of BiFeO 3 -based films in devices particularly for potential application at elevated temperature. [ABSTRACT FROM AUTHOR]

SiO2 is an important modally abundant component of terrestrial planets, while there are few studies that quantitatively determine the properties of silica under simultaneously high‐temperature and high‐pressure conditions. In this study, thermal properties of stishovite, CaCl2‐type SiO2 and seifertite have been obtained by using extensive first‐principles simulations. The quasi‐harmonic approximation and intrinsic anharmonic effects were considered, and a generalized rescaling method was adopted to eliminate systematic errors in the simulation results. Based on the simulation data, we have established new equations of state for the SiO2 polymorphs and determined their phase boundaries. Anharmonicity has been demonstrated to show noticeable effects on their thermal properties and phase boundaries. With the new results, we found that SiO2 polymorphs show increasing buoyancy in the subducted basaltic slabs at depths greater than ∼800–900 km. In the normal lower mantle, they are readily stable over a broad range of depths approximately from 1,500 km to 2,600 km. This implies that SiO2 polymorphs may contribute to the lateral heterogeneity in the deep lower mantle as observed by small‐scale seismic scatterers. Plain Language Summary: The solid Earth is mainly composed of silicates and SiO2 is an important endmember. Previous experiments and theoretical calculations show that SiO2 has three high‐pressure phases, stishovite, CaCl2‐type SiO2 and seifertite under lower mantle conditions. These phases may be related with the regional velocity anomalies in the lower mantle, so it is vital to accurately determine their thermal properties and the locations of phase transitions. In this study, based on extensive high quality first‐principles simulations, we have established new thermodynamic models for the three high‐pressure phases and predicted phase transition boundaries that are in good agreement with experiments. Our results show that SiO2 would meet its neutral buoyancy at about 800–900 km in the typical subduction slabs. Meanwhile, its density keeps being close to the averaged density in the normal lower mantle from ∼1,500 km to ∼2,600 km. These findings give important hints on the fate of SiO2 high‐pressure phases in the deep mantle. Key Points: We obtained the equations of state of stishovite, CaCl2‐type SiO2, and seifertite based on extensive first‐principles simulationsAnharmonicity is important at high temperatures and has noticeable effects on phase boundariesSilica polymorphs can be stable and related with the small‐scale seismic scatterers in the deep lower mantle [ABSTRACT FROM AUTHOR]

Mechanical friction leads to wear and energy dissipation, and its control is of high importance in new‐generation miniature electromechanical devices. 2D materials such as graphene are considered to be excellent solid lubricants due to their ultralow friction and have attracted considerable research interest. Unique friction properties are discovered in various other 2D materials. However, the friction of functional van der Waals materials which have potential applications in novel nanoelectronics, like ferroelectric copper indium thiophosphate, has barely been studied. Herein, the study reports on the observation of inhomogeneous friction behavior existing in copper‐deficient CuInP2S6 (Cu0.2In1.26P2S6), which exhibits a nanoscale phase separation of polar and non‐polar crystalline phases. The paraelectric In4/3P2S6 phase exhibits higher friction than the ferroelectric CuInP2S6 phase, while phase boundaries between the two phases, interestingly, display the lowest friction. The origin of this phenomenon is attributed to different lattice strains of phases together with the presence of large strains at the nanoscale phase boundaries, which also manifests in the nonuniform tip‐sample adhesion force. The findings provide new insights into nanoscale device design and wear behavior of a phase‐separated van der Waals ferroelectric, which may help to reduce the power consumption of friction‐exhibiting devices and extend their service life. [ABSTRACT FROM AUTHOR]

Mechanical friction leads to wear and energy dissipation, and its control is of high importance in new‐generation miniature electromechanical devices. 2D materials such as graphene are considered to be excellent solid lubricants due to their ultralow friction and have attracted considerable research interest. Unique friction properties are discovered in various other 2D materials. However, the friction of functional van der Waals materials which have potential applications in novel nanoelectronics, like ferroelectric copper indium thiophosphate, has barely been studied. Herein, the study reports on the observation of inhomogeneous friction behavior existing in copper‐deficient CuInP2S6 (Cu0.2In1.26P2S6), which exhibits a nanoscale phase separation of polar and non‐polar crystalline phases. The paraelectric In4/3P2S6 phase exhibits higher friction than the ferroelectric CuInP2S6 phase, while phase boundaries between the two phases, interestingly, display the lowest friction. The origin of this phenomenon is attributed to different lattice strains of phases together with the presence of large strains at the nanoscale phase boundaries, which also manifests in the nonuniform tip‐sample adhesion force. The findings provide new insights into nanoscale device design and wear behavior of a phase‐separated van der Waals ferroelectric, which may help to reduce the power consumption of friction‐exhibiting devices and extend their service life. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Jilin University (Science Edition) / Jilin Daxue Xuebao (Lixue Ban) is the property of Zhongguo Xue shu qi Kan (Guang Pan Ban) Dian zi Za zhi She and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Under high pressures, many crystalline metals undergo solid–solid phase transformations. In order to accurately model the behavior of materials under extreme loading conditions, it is essential to understand the kinetics of phase transition. Using molecular dynamics simulations, this work demonstrates the feasibility of characterizing the speeds of a moving phase boundary using atomistic simulations employing a suitable empirical potential for single-crystal magnesium. The model can provide temperature- and tensorial stress-dependent velocity of a moving phase boundary as a rate-limiting contribution to the kinetics of phase transformation in continuum codes. Results demonstrate that a nonlinear interaction exists between plasticity and phase transition, facilitating a jump in the velocity of a moving phase boundary, facilitated by activated plastic deformation mechanisms.

Both high pyroelectric coefficient and figure of merits of ferroelectric materials are desirable for infrared detection. In this work, we prepared Pb0.99Nb0.02[(Zr0.57Sn0.43)1−xTix]0.98O3 (0.060 ≤ x ≤ 0.080) ceramics, and the microstructure and electric properties were studied systematically. It is observed that the composition x = 0.07 shows enhanced pyroelectric properties around ambient temperature due to the ferroelectric–antiferroelectric phase transition, with the pyroelectric coefficient p = 6.83 × 10−4 C m−2 K−1 and the figures of merit Fi = 5.04 × 10−10 m V−1, Fv = 7.61 × 10−2 m2 C−1, and Fd = 3.46 × 10−5 Pa−1/2 at room temperature and the highest pyroelectric coefficient of 695.5 × 10−4 C m−2 K−1 and Fi = 1410.46 × 10−10 m V−1, Fv = 1587.39 × 10−2 m2 C−1, and Fd = 1182.94 × 10−5 Pa−1/2 at 36.7°C. These values are superior to other pyroelectric materials. These results indicate that this system is a promising pyroelectric material for the applications of infrared detectors. [ABSTRACT FROM AUTHOR]

Cell-based screening methods are increasingly used in diagnostics and drug development. As a result, various research groups from around the world have been working on this topic to develop methods and algorithms that increase the degree of automation of various measurement techniques. The field of computer vision is becoming increasingly important and has therefore a significant influence on the development of various processes in modern laboratories.In this work we describe an approach for detecting two height information, the phase boundary of a cell pellet and the bottom edge of the tube, and thereby a method for determining the highest point of the topology. The starting point for the development of the method described are cells obtained by various procedures and stabilized by a fixative. Centrifugation of the tube causes the cells to settle to the bottom of the tube, resulting in a cell pellet with a clear phase boundary between the cells and the fixative. For further studies, the supernatant fixative has to be removed without reducing the number of cells. The fixative is to be extracted automatically by a liquid robot, which is only possible by accurately determining the cell pellet height. Due to centrifugation, an uneven topology is formed, which is why the entire phase boundary must be examined to detect the highest point of the cell pellet.For this approach, the tube to be examined, which contains the cells and the fixative, is rotated 360° in defined small steps after centrifugation. During rotation, an image is captured in each step, after which a defined image area is separated from the center of the image and merged into a panoramic image. This produces a panoramic image of the cell topology which represents the complete phase boundary, the boundary located on the outside of the tube. This panoramic image is modified through various image processing steps to extract and detect the phase boundary. Various image processing algorithms from the OpenCV library are used. In the first step, the panoramic image is convolved with a Gaussian blur filter to reduce noise. In the following step, a black and white image is generated by a thresholding process. This black and white image, or binary image, is convolved with a Sobel operator in the x and y directions and the results are superimposed. This overlaid image shows the top edge of the cell pellet and other edges located in the image. A logical exclusion method of the obtained boundaries is used for the detection of the phase boundary. To detect the tube bottom, a multilevel model was trained in advance with an appropriate data set. This model can detect and localize in near real time the tube bottom in an image.By using the two-height information of the different boundaries, phase boundary and tube bottom, the highest point of the cell pellet can be detected. This information is then passed on to a higher-level process so that the liquid robot can approach this point with the pipette tip to remove the excess fixative. By determining the highest point, the probability of being able to remove a larger amount of fixative without reducing the number of cells is highest. This ensures that post-processing studies have the largest possible number of cells available with complete automation.

Microemulsion biofuels can become one of alternative biodiesels using suitable nonionic surfactants and cosurfactant to emulsify vegetable oil and ethanol with the appropriate formulae. Without the further chemical improvement, the low volatility and high viscosity because of triglycerides in vegetable oil can cause a serious problem in engine operation. This work proposed a systematic investigation of microemulsion biofuel prepared from rice bran oil and ethanol using mixed nonionic surfactant systems (Dehydol LS7, Tween 80, and Span 80) as surfactant (S) and 1-octanol as a cosurfactant (C) at molar ratio of 1:30. Microemulsion phase behaviors can be examined through the ternary phase diagram of rice bran oil, ethanol, and S:C. It was observed that Dehydol LS 7 was poor in solubilization of rice bran oil and ethanol because of their preference in hydrophilic compounds rather than lipophilic compounds. Introduction of Tween 80 or Span 80 into the biofuels using Dehydol LS 7 enhanced the solubilization of these systems as the extent of single-phase boundary was significantly enlarged because of the hydrophilic–lipophilic balance of the mixture and chemical structure of surfactants. The fuel properties of microemulsion biofuel were investigated through kinematic viscosity, specific gravity, flash point, cloud point, pour point, and higher heating value. It was found that mixed surfactant also improved some fuel properties due to additional surfactants contain many oxygenated functional groups, however, some parameters were slightly substandard. The combustion characteristics and exhaust emission were investigated in CI diesel engine. It was observed that the in-cylinder pressure was lower under the combustion of microemulsion fuel mainly due to the high latent heat of vaporization of alcohols. The start of combustion was more retarded with the addition of Span 80, especially at low load condition. It was observed that the significant reduction in nitrogen oxides was achieved with the combustion of microemulsion fuel while unburnt hydrocarbon emissions were higher compared to diesel fuel. The obtained experimental data showed that microemulsion biofuels can be a promising alternative biodiesel although the individual usage in engine was slightly less efficient than commercial diesel fuel.

This article discusses the problems of studying the issue of joint motion of liquids in the porous space. The article provides the construction of a mathematical model of the theory of ltration, which describes phase transitions. The main diculty in constructing this model is associated with the fact that free interphase boundaries create regions that change over time, and it is required to nd the temperature or concentration elds of substances in them. In this case, the coordinates of the considered phase boundaries are not initially specied and must be calculated already in the process of solving. For this, a derivation of the averaged equation for the problem of nding the rupture surface during the movement of two incompressible viscous liquids in the pores of the soil skeleton was proposed. The article deals with the case when the skeleton is an absolutely rigid body. The rationale was given for the choice of an averaged ltration model instead of a microscopic one. The main research methods are classical methods of mathematical physics, functional analysis and computation methods of the theory of partial dierential equations, as well as dierence methods. The formulation of the problem is given, and the denition of a generalized solution for solving the problem is provided. Next, an averaged model is derived and the existence of at least one generalized solution to the problem is proved.

Achieving excellent pyroelectric performance remains a challenge for lead‐free piezoelectric ceramics. To meet the requirements of both an enhanced pyroelectric coefficient at room temperature and good thermal stability during the encapsulation of pyroelectric devices, (1–x)K0.48Na0.52NbO3–xBi0.5Ag0.5ZrO3–0.2%Fe2O3 (KNN–BAZ–Fe) lead‐free ferroelectric ceramics with high Curie temperatures were prepared to obtain improved pyroelectric performance via the coexistence of multiple symmetries. The variation of BAZ content led to the formation of rhombohedral–orthorhombic–tetragonal phase boundary and promoted grain growth, resulting in the best pyroelectric coefficient (p = 5.09 × 10−4 C m−2°C−1) and enhanced figures of merit (Fi = 0.2084 × 10−9 (m V−1), Fv = 0.0142 m2 C−1, Fd = 0.0947 × 10−4 Pa−1/2, and Fe = 17.66 J m−3 K−2) for infrared (IR) detection when x = 0.05. The room‐temperature pyroelectric coefficient obtained in this study is approximately four times that of the pure KNN ceramic and is the maximum value reported for niobate‐based piezoelectric ceramics. Moreover, compared with the poor thermal stability of barium titanate‐ and bismuth sodium titanate‐based ceramics because of their ultralow Curie temperature or thermal depolarization temperature, the ceramics investigated here exhibit much better thermal stability because of their high Curie temperature (TC > 300°C) and diffused phase‐transition behavior, making them more adaptable for practical applications. These results suggest that KNN–xBAZ–Fe ceramics are attractive candidates for applications in the field of IR sensors. [ABSTRACT FROM AUTHOR]

We celebrate the legacies of our friend and mentor Professor Lianshou Liu who was one of the pioneers for the phenomenology of multi-particle interactions and initiated the physics of relativistic heavy-ion collisions in China. In this article, we discuss some of the recent exciting experimental observations on the collective phenomena including collectivity, chirality, criticality, strangeness production, and thermal equilibrium in high-energy nuclear collisions. Future directions, especially the physics at high baryon density, will be discussed with a focus on the first-order phase boundary and hyperon–nucleon interactions. [ABSTRACT FROM AUTHOR]

[Display omitted] • The KNN6L-PDMS porous composites have been successfully achieved with both the excellent piezoelectric properties and mechanical flexibility. • The piezo-catalytic activity exhibited a high efficiency and superior repeatability for degrading organic pollutants. • COMSOL simulations determined that piezo-catalysis was originated from the generated potential of piezoelectric composites. Piezoelectricity as a physical property has received great attention due to its excellently functional applications, especially in piezoelectric catalysis and mechanical energy harvesting. To take full advantage of the functions of piezoelectric materials, (K 0.5 Na 0.5) 0.94 Li 0.06 NbO 3 (KNN6L) piezoelectric powders were compounded with polydimethylsiloxane (PDMS) in this work. The developed KNN6L-PDMS porous piezoelectric composites with flexible and recyclable characteristics could achieve ∼ 91% degradation rate of Rhodamine B (RhB) dye wastewater under mechanical vibration, and the outstanding piezocatalytic activity was still maintained after repeated decomposition multiple times. Besides, the relationship between piezoelectric potential and piezocatalysis was validated by COMSOL simulations. The content of piezoelectric powders played a positive effect on the magnitude of piezoelectric potential generated by the KNN6L-PDMS porous composites. Moreover, the catalytic mechanism was found to be originated by generation of various reactive oxygen species (mainly •O 2 – and •OH) in water environment as a result of strong piezoelectric effect by the porous composites. The porous piezoelectric composites with flexible and recyclable characteristics exhibited excellent performance in piezoelectric catalysis which has promising applications in the field of environmental remediation. [ABSTRACT FROM AUTHOR]

The paper reports the results of experimental and numerical studies of vortex motion in an industrial-scale glass bioreactor (volume, 8.5 L; reactor vessel diameter D, 190 mm) filled 50–80%. The model culture medium was a 65% aqueous glycerol solution with the density ρg = 1150 kg/m3 and kinematic viscosity νg = 15 mm2/s. The methods of particle image velocimetry and adaptive track visualization allow one to observe and measure the vortex motion of the culture medium. In this work, the vortex flow investigation was performed in a practical bioreactor at the operation regimes. Our research determines not only the optimal flow structure, but also the optimal activator rotation speed, which is especially important in the opaque biological culture. The main result is that, similar to the case of two rotating immiscible liquids, a strongly swirling jet is formed near the axis, and the entire flow acquires the pattern of a miniature gas–liquid tornado. The aerating gas interacts with the liquid only through the free surface, without any mixing. This intensifies the interphase mass transfer due to the high-speed motion of the aerating gas. [ABSTRACT FROM AUTHOR]

Recently, piezocatalytic technology has been recognized as an efficient and viable strategy for the remediation of aquatic environments. Herein, a synergistic strategy of phase boundary and defect co-engineering has been proposed to enhance the piezocatalytic performance of BaTiO 3 -based ceramic materials: a ceramic system material ((1- x)BaTiO 3 - x (Ca 0.9 Sr 0.1)(Sn 0.5 Hf 0.5)O 3 , (1- x)BT- x CSSH) was constructed to achieve the coexistence of multiple ferroelectric phases by co-doping ions in the A/B-sites, and defect engineering was realized by a high-temperature annealing. The 0.95BT-0.05CSSH ceramic exhibits the coexistence of rhombic (R), orthorhombic (O), and tetragonal (T) phases, with multiple spontaneous polarization directions and low polarization rotational energy barriers, thereby demonstrating high piezoelectricity (d 33 = 450 pC/N) and thus outstanding piezocatalytic performance. The degradation rate/reaction rate constant of the 0.95BT-0.05CSSH ceramic material for rhodamine B (RhB) is 71.35 %/13.5 × 10−3 min−1. After undergoing a high-temperature annealing, the catalytic activity of the 0.95BT-0.05CSSH ceramic is further improved, resulting in a degradation rate/reaction rate constant of 92.84 %/28.5 × 10−3 min−1 for rhodamine B (RhB). The catalytic activity of the 0.95BT-0.05CSSH material is enhanced by the generation of abundant oxygen vacancies during high-temperature annealing, which facilitates the separation and migration of electron-hole pairs. In this study, we propose a novel strategy to upgrade the piezocatalytic performance of BaTiO 3 -based piezoelectric materials, which is useful for the remediation of aquatic environments. • Phase boundary and defect co-engineering to boost the piezocatalytic performance of BaTiO 3 -based materials. • Coexistence of R-O-T phases can be realized by doping Ca2+/Sr2+ at the A-site and Sn4+/Hf4+ at the B-site of BaTiO 3. • High temperature annealing can increase oxygen vacancies in the material. • The 0.95BT-0.05CSSH-700 material have excellent piezocatalytic performance. [ABSTRACT FROM AUTHOR]

Irradiation damage and thermal aging greatly affect the phase boundary microstructure and stress corrosion cracking of austenitic stainless steel weld metals (ASSWMs) in water-cooled nuclear reactors. However, the effects of irradiation plus thermal aging (I + A) on the phase boundary segregation and phase changes remain unclear. Phase changes and elemental segregation at the carbide and carbide-free phase boundaries of 308 L ASSWMs after I + A treatment were investigated using atom probe tomography and transmission electron microscopy. The I + A treatment induced Si depletion at the phase interfaces of δ-ferrite/austenite (δ/γ) and δ-ferrite/carbide (δ/C) and also induced Ni enrichment and Cr depletion with concentrations having the order Ni/Cr(δ/γ) > Ni/Cr(δ/C) > Ni/Cr(γ/C). The solute-defect binding model and the vacancy mechanism were applied to explain the phase boundary segregation. Furthermore, the I + A treatment affected microstructural evolution near the phase boundaries; this reduced spinodal decomposition and inhibited G-phase and Ni/Si-rich-cluster formation. The phase separation of δ-ferrite near δ/γ and δ/C phase boundaries differed with the distance from the boundary, forming a gradient microstructure from phase boundaries to δ-ferrite internally. The gradual precipitation of the G-phase was observed beyond about 15 and 10 nm from the δ/γ and δ/C interfaces, respectively; moreover, the growth of α'-phase in the δ-ferrite was accelerated with increasing distance from the δ/γ and δ/C interfaces. [Display omitted] • I + A treatment induced Ni enrichment and Cr depletion at the phase boundaries. • I + A treatment enhanced spinodal decomposition within δ-ferrite, but reduced it near the phase boundary. • The G phases gradually precipitated at ∼ 15 and ∼ 10 nm away from the δ/γ and δ/C interfaces, respectively. • No G phase precipitated near phase boundary because of Ni deficiency for G-phase formation near δ/γ and δ/C interfaces. • The formation of Ni/Si-rich clusters near the phase boundary was inhibited after I + A treatment. [ABSTRACT FROM AUTHOR]

Relaxor ferroelectric films have been widely studied for applications in miniaturized advanced pulsed power devices due to their fast charging and discharging rates and very fine polarized electric field hysteresis, which can be designed by incorporating paraelectric components into the ferroelectrics. In this work, lead-free BaTiO 3 -based relaxor ferroelectric films are achieved by formulating solid solutions of ferroelectric BaTiO 3 with the paraelectric BaZrO 3. The optimized energy storage performance is achieved at the ferroelectric-relaxor ferroelectric phase boundary in the BaZr 0.3 Ti 0.7 O 3 films with an improved recoverable energy storage density of 58.6 J/cm3 and an energy storage efficiency of 71 % at 3600 kV/cm due to the increased maximum polarization. In addition, frequency-insensitive stability from 100 Hz to 10 kHz, long-term fatigue resistance up to 107 switching cycles, and high-temperature stability in the range of 20 °C–100 °C are achieved. The work offers a good strategy via creating a phase boundary for improving the energy storage performance in the BaTiO 3 -based relaxor ferroelectric films for advanced energy storage dielectric capacitors. • Energy density of 58.6 J/cm3 and efficiency of 71 % are realized in Ba 0.3 Zr 0.7 TiO 3 thin film. • High frequency, temperature and anti-fatigue stability are achieved. • Enhanced energy storage is acquired at ferroelectric-relaxor ferroelectric phase boundary. [ABSTRACT FROM AUTHOR]

• The structure of several different kinds of phase boundaries existing in MRR can be modeled on the basis of STM investigations. • As the result of the regulation effect of phase boundaries, MRR domains along the phase boundaries exhibit prominent orientation preference with the degree closely related with the width of the boundaries. • The potential origination of different phase boundaries are analyzed according to their preparation conditions and structural features. Although the structure of Cu(100)-(2 2 × 2) R 45°-O missing row reconstruction (MRR) has been well-established for decades, the detailed structure of its various boundaries remains an untilled area due to the difficulties in obtaining atomically resolved images. Herein, atomic arrangement of the phase boundaries existing in MRR structure was modeled on the basis of scanning tunneling microscopy (STM) investigations. By determining the periodicity and unit structure of MRR in STM images and extending them to boundary region, several types of phase boundaries were identified, resulted respectively from: (1) the mismatch between c (2 × 2)-O patches, (2) the regulation by step edges, and (3) the mismatch between Cu missing rows (MRs). With the modeled structure, it was revealed that the types of the c (2 × 2)-O mismatch induced phase boundaries (OMIPBs) are mainly dominated by the oxygen exposure and in-diffusion barrier. The step edge regulated phase boundaries (SERPBs) are always terminated with Cu-O chain and may represent an intermediate growth stage to larger MRR structure. Comparatively, Cu MRs mismatch is often reconciled by the differently oriented domains between them. As a result, the Cu MRs mismatch induced phase boundaries (CMRMIPBs) are only occasionally observed as Cu-O chains between mismatched Cu MRs that encounter shoulder-to-shoulder. For all studied boundaries, the surrounding MRR domains exhibit obvious orientation preference through inclined packing along the SP direction with the degree closely related with the width of the boundaries. The atomic arrangement of phase boundary existing in (2√2 ⅹ √2)R45°-O missing row reconstruction (MRR) phase on Cu(100) is modeled on the basis of STM investigation and correlated with the physicochemical properties of materials. [Display omitted] [ABSTRACT FROM AUTHOR]

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Experimental studies are carried out to determine the structure of the pore space of MGA-95 and ESPA reverse-osmosis membranes by small-angle X-ray scattering. The numerical values of the pore radii are established as parameters that form the skeleton of the pore space of reverse-osmosis composite membranes. It is noted that the membrane space is formed by homogeneous pores of different sizes and shapes, and the membranes have scattering centers in the form of extended straight and tortuous channels formed from chains of spheres (pores), i.e., the model of "stacked spheres." Studies of the resistance and membrane potential in semipermeable membranes MGA-100 and MGA-95 are carried out in a specially designed cell. Experimental data are obtained that indicate that at a certain point in time dynamic equilibrium occurs between the hydrodynamic force determined by the osmotic pressure and the electromotive force of the membrane potential. This phenomenon is associated with the relaxation time (permeability coefficient). The zeta potential changes sign from negative in the case of water sorption to positive during osmosis. The sorption coefficients, permeability and zeta potential for reverse-osmosis cellulose-acetate membranes of the MGA-95 and MGA-100 types are calculated. [ABSTRACT FROM AUTHOR]

A new programed upper critical solution temperature-type thermoresponsive polymer was developed using water-soluble anionic polymer conjugates derived from polyallylamine and phthalic acid with cleavage-induced phase transition property. Intrinsic charge inversion from anion to cation of the polymer side chain is induced through a side chain cleavage reaction in acidic aqueous media. With the progress of side chain cleavage under fixed external conditions, the polymer conjugates express a thermoresponsive property, followed by shifting a phase boundary due to the change in polymer composition. When the phase transition boundary eventually reached the examined temperature, phase transition occurs under fixed external conditions. Such new insight obtained in this study opens up the new concept of time-programed stimuli-responsive polymer possessing a cleavage-induced phase transition. [ABSTRACT FROM AUTHOR]

Dynamic control of thermal transport in solid materials is highly desired for thermal management technology. However, the development of a material exhibiting large modulation of thermal conductivity (κ) by external stimuli remains a major challenge. Here, the large κ modulation is reported by the reversible 3D to 2D crystal structure transition in a nonequilibrium solid solution of (Pb1−xSnx)Se, where Pb2+ stabilizes a 3D cubic structure while Sn2+ does a 2D layered structure. The phase boundary of these phases is induced in (Pb0.5Sn0.5)Se bulk polycrystals by thermally quenching the high‐temperature solid solution phase. Through the 3D–2D phase transition, the 1/2.9‐times decrease of lattice κ (κlat.) is achieved by strong phonon scattering in the 2D layered structure, and the electronic κ (κele.) is also decreased by 5 orders of magnitude due to the electronic phase transition from a 3D high conductivity state to a 2D semiconducting state. The total κ (=κlat. + κele.) modulation ratio κ3D phase/κ2D phase = 3.6 is attained at 373 K. The present strategy will lead to a novel concept for designing thermal management materials through crystal‐structure dimensionality switch using nonequilibrium phase boundaries. [ABSTRACT FROM AUTHOR]

Abstract Biphasic and multiphasic compounds have been well clarified to achieve extraordinary electrochemical properties as advanced energy storage materials. Yet the role of phase boundaries in improving the performance is remained to be illustrated. Herein, we reported the biphasic vanadate, that is, Na1.2V3O8/K2V6O16·1.5H2O (designated as Na0.5K0.5VO), and detected the novel interfacial adsorption–insertion mechanism induced by phase boundaries. First‐principles calculations indicated that large amount of Zn2+ and H+ ions would be absorbed by the phase boundaries and most of them would insert into the host structure, which not only promote the specific capacity, but also effectively reduce diffusion energy barrier toward faster reaction kinetics. Driven by this advanced interfacial adsorption–insertion mechanism, the aqueous Zn/Na0.5K0.5VO is able to perform excellent rate capability as well as long‐term cycling performance. A stable capacity of 267 mA h g−1 after 800 cycles at 5 A g−1 can be achieved. The discovery of this mechanism is beneficial to understand the performance enhancement mechanism of biphasic and multiphasic compounds as well as pave pathway for the strategic design of high‐performance energy storage materials.

The aim of the study is the development of two-layer materials based on ultra-high-molecular-weight polyethylene (UHMWPE) and isoprene rubber (IR) depending on the vulcanization accelerators (2-mercaptobenzothiazole (MBT), diphenylguanidine (DPG), and tetramethylthiuram disulfide (TMTD)). The article presents the study of the influence of these accelerators on the properties and structure of UHMWPE. It is shown that the use of accelerators to modify UHMWPE leads to an increase in tensile strength of 28–53%, a relative elongation at fracture of 7–23%, and wear resistance of three times compared to the original UHMWPE. It has been determined that the introduction of selected vulcanization accelerators into UHMWPE leads to an increase in adhesion between the polymer and rubber. The study of the interfacial boundary of a two-layer material with scanning electron microscopy (SEM) and infrared spectroscopy (FTIR) showed that the structure is characterized by the presence of UHMWPE fibrils localized in the rubber material due to mechanical adhesion. [ABSTRACT FROM AUTHOR]

Tin (Sn)-based materials are promising anodes for magnesium-ion batteries (MIBs) owing to their low reaction voltages, high theoretical specific capacities and good compatibility with conventional electrolytes. However, relatively arduous alloying reaction and sluggish diffusion kinetics limit their practical applications. Herein, we proposed a general strategy to regulate the electrochemical reactivity and performance of Sn-based anodes for Mg storage through the introduction of the second phase and phase boundary. The biphase Sn—Al, Sn—Pb and Sn—ZnO films were further fabricated via magnetron co-sputtering. Taking Sn—Al as an example, it has been revealed that the introduction of Al can effectively stimulate the electrochemical reaction of Sn with Mg in either nanoscale or bulk through combining experiments with density-functional theory calculations. Specially, the rolled Sn—Al electrode exhibits superior long-term stability over 5,000 cycles. Additionally, the Mg-storage mechanism of the Sn—Al electrode was investigated by operando X-ray diffraction. The Sn—Al anodes also demonstrate good compatibility with simple Mg-salt-based electrolytes like Mg(TFSI)2 in full cells. More importantly, it has been authenticated that the activation effect of second phase and phase boundary to Sn is also applicable to Pb and ZnO. Our findings may provide a favorable reference for the development of alloy-type anodes for MIBs. [ABSTRACT FROM AUTHOR]

Polysynthetic twinned (PST) TiAl single crystals, consisting of alternating layers of γ-TiAl and α 2 -Ti 3 Al, exhibit excellent mechanical properties. However, size-dependent deformation mechanisms have not yet been fully elucidated. In this work, we investigated the deformation process of two-phase γ-TiAl/α 2 -Ti 3 Al alloys with different layered sizes via uniaxial tensile loading using molecular dynamics simulations. The results show that with the decreasing phase boundary (PB) spacing λ or domain boundary (DB) spacing d , the excess free volume at the intersection of DB and PB decreases, leading to increased yield stress. We found that a higher interface density (smaller λ or d) can accommodate more dislocations, and the size-dependent ultimate strength follows an approximate Hall-Petch relation. These findings offer an essential understanding for the size-dependent PST TiAl single crystals with high strength. [Display omitted] [ABSTRACT FROM AUTHOR]

Interphase boundary plays a dominant role in the mechanical properties of dual-phase titanium alloys, and therefore mechanistic understandings of the effect of phase boundary on the plasticity is significant to tailor the microstructure for desired performance. In this study, compression tests were conducted on the Ti-6Al-4V micro-pillars with a dual-phase lamellar structure and designated crystallographic orientation of pillars and the number of interphase boundaries in the pillars were achieved by elaborate processing, to reveal the interphase boundary and its quantity on the dislocation behavior and critical resolved shear stress (CRSS) of the alloy. Transmission electron microscopy was employed to characterize the dislocations and their interplay with interphase boundaries during compression. It is found that in the pillars oriented for prismatic 〈a 3 〉 slip, which represents the hard mode for dislocation transmission through the α/β phase boundary, the strain distribution in the pillars was significantly delocalized by introducing interphase boundaries. More dislocation slip bands are generated owing to the strengthening effect from the interphase boundaries during compression, which results in a more homogeneous strain distribution. Moreover, quantitative analyses of the contribution of interphase boundaries on the CRSS were performed, and the interphase strength for prismatic 〈a 3 〉 slip was experimentally determined to be ∼ 50 MPa. The effect of pillar size on the CRSS value was also assessed. Although the CRSS of the pillars increases when their size decreases, the size dependency becomes much less pronounced when more interphase boundaries are introduced into the pillars. The underlying mechanisms for these phenomena were discussed based on the experimental results and finite element modeling. These results provide some new insights into the plasticity and strengthening mechanism of Ti-6Al-4V alloy, which are also applicable to other dual-phase titanium alloys. [Display omitted] [ABSTRACT FROM AUTHOR]

W–Cu composites are integrated materials with both structural and functional properties. However, the weak interfacial bonding capability leads to limited strain hardening, which makes it difficult to take full advantage of the coordination of the biphasic materials. In present work, a multistage strain-hardening (MSH) effect is created, which enables the W–Cu composites to possess a persistent and effective strain-hardening capability. The prepared W-30(CuAl5) (wt.%) alloy has significant tensile ductility (∼21 %) and ultra-high yield strength (∼840 MPa). Remarkably, compared to the original W–30Cu without Al alloying, the strength and ductility are over two and three times, respectively, accompanied by the preservation of an electrical conductivity of about 80 %. This excellent synergistic effect stems from the Al-mediated interpenetrating interfacial diffusion layers and matrix-nanoclusters interconnection networks. As a result, a high-density of dislocation segments, self-locking structures, and a variety of twinning mechanisms such as nanotwins and 9R configurations are sequentially activated, allowing the composites to accommodate ductility deformation while simultaneously facilitating interactions that produce three unusual rises in strain-hardening rate. The present work offers a critical perspective on the realization of a synergistic ultrahigh tensile ductility and strength combination in metal matrix composites. [Display omitted] • Multistage strain hardening strategy was built in W–Cu immiscible composites. • The strength and ductility were doubled and tripled with Al alloying. • Redistributed interpenetrating interface enhanced the bonding strength. • Matrix-nanocluster coupling network was formed to alter dislocation dynamics. • Rough stacking fault energy topography generated diverse SF and twin structures. [ABSTRACT FROM AUTHOR]

[Display omitted] • The coexistence of orthorhombic and tetragonal phase boundaries was successfully realized in CeO 2 -modified BCZT piezoelectric materials at room temperature. • Outstanding piezocatalytic performance was achieved in the BCZT-0.04CeO 2 , and the piezoelectric catalytic activity exhibited excellent reproducibility for the degradation of organic pollutants. • Catalytic degradation in the dark field utilizes the mechanical energy. Piezoelectric catalysis can drive pollutant degradation by means of piezoelectric effect with mechanical–electrical energy conversion. Here, we propose to modulate the phase boundary in CeO 2 doped (Ba 0.85 Ca 0.15)(Zr 0.1 Ti 0.9)O 3 compounds (BCZT-CeO 2) to improve piezoelectric catalytic activity. The interrelationships between composition, phase structure, electrochemistry, and catalytic performance were methodically examined. BCZT-0.04 wt%CeO 2 coexists in orthorhombic and tetragonal phases with a high piezoelectric coefficient (d 33 = 425 pC/N) and demonstrates enhanced piezoelectric catalytic performance. The polarized BCZT-0.04 wt%CeO 2 acquires the remarkable degradation ratio of 92.5 % for Rhodamine B dye within 60 min. The enhancement of piezo-catalytic activity was further identified through the electrochemical analysis and hence the reasonable mechanism of polarization-induced charge transfer was proposed for piezoelectric catalysis as well. This work provides a promising strategy for boosting the piezoelectric catalytic performance under phase boundary engineering and potentially extends the application range of lead-free ferroelectric materials, typically towards pollutant treatment. [ABSTRACT FROM AUTHOR]

• The substructure of a twin and of a tilt/twist Zr 2 Si/Zr 2 Si interfaces was analysed. • The Zr 2 Si/Zr 2 Si twin boundary was a singular interface containing disconnections. • The small angle Zr 2 Si/Zr 2 Si mixed tilt-twist boundary was a vicinal interface. • Defects were induced by HCP-Zr to FCC-Zr transformation around Zr 2 Si precipitate. This work investigates the atomic scale substructure of interfaces in Zr 2 Si secondary phase precipitates formed by the stresses associated with the α-Zr (HCP) to γ-Zr (FCC) phase transformation and thermal effects in an experimental Si-modified Zircaloy-4 by means of transmission electron microscopy and CSL/DSCL (coincident site lattice/displacement shift complete lattice) models. Analysis of a high-angle twin interface reveals their characteristic principal primary Δ g vectors, a typical feature of the singular interfaces, and the sessile twinning disconnections. The step height and length of the interfacial dislocation line, with the Burgers vector parallel to the habit plane, are analysed using the DSCL model. In the second case, a low-angle interface of mixed tilt-twist character is studied and facets of constant length along the densest-packed planes and ledges of inconstant height, a common feature of vicinal interfaces, are identified. [Display omitted] [ABSTRACT FROM AUTHOR]