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Core-shell structured copper-boron nitride (Cu@BN) spherical fillers were synthesized to fabricate thermally conductive composites. To enhance the interaction between the fillers and the matrix, polysilazane (PSZ) was coated on the surface of the filler. The resultant composite exhibited remarkable characteristics, including a substantial tensile strength of 32.36 MPa, excellent electrical insulation properties, and impressive thermal conductivity of 3.47 W/mK. When applied in a light-emitting diode (LED) application, the composite effectively managed heat, reducing the operating temperature by 34 °C. The epoxy/PSZ-Cu@BN composites hold great promise for improving thermal management in electronic devices. • The copper-boron nitride (CuBN) core-shell structured filler was fabricated. • The PSZ coating of CuBN reinforced thermal and mechanical properties of composites. • The Epoxy/PSZ-CuBN composites achieved high thermal management performance. [ABSTRACT FROM AUTHOR]

In this study, SiCp-SiO 2 /6061Al composites were synthesized by integrating SiC and SiO 2 particulates into a 6061Al matrix, followed by ball milling and hot isostatic pressing sintering. The impact of ball milling duration on microstructure, mechanical properties, corrosion resistance, and thermal properties was evaluated. After 10 h of ball milling, reinforcement particles were uniformly dispersed, achieving a material density of over 98 %. Extending milling to 15 h enhanced tensile strength to 253.53 MPa and flexural strength to 433.56 MPa, with a maximum elongation at break of 6.4 %. Uniform SiO 2 distribution improved corrosion resistance, evidenced by a self-corrosion potential of −1209 mV and a self-corrosion current density of 53.02 µA·cm−2. After 20 h, the lowest thermal expansion coefficient, 19.87×10−6·K−1, was achieved. However, agglomerated particles after 5 h resulted in inferior thermal properties, including a thermal expansion coefficient of 20.45×10−6·K−1 and thermal conductivity of 94 W·m−1·K−1. The optimal ball milling duration for these composites was determined to be 10 h, balancing performance and cost-effectiveness. • High Performance and Versatility: The composite material exhibits excellent mechanical strength and ductility, with enhanced thermal stability. After 15h of ball milling, it achieved a tensile strength of 253.53 MPa and an elongation at break of 6.4 %, with an average thermal expansion coefficient of 20.26×10−6·K−1 between 25 and 300℃. These properties make it ideal for applications in the aerospace, automotive, and electronics industries. • Enhanced Corrosion Resistance: Uniform SiO 2 distribution after 15 h ball milling significantly enhances corrosion resistance. • Optimized Thermophysical Properties: SiO 2 reinforcements reduce thermal expansion coefficient and enhance the stability of composites; milling time also impacts thermal properties. [ABSTRACT FROM AUTHOR]

Phase change materials (PCM) have attracted much attention in the field of thermal energy storage because of exceptional heat storage capacity, stable operating temperature, and recyclability. However, organic phase change materials, represented by palmitic acid (PA), are limited by inherent leakage problem, unsatisfactory thermal responsiveness and inefficient photo-thermal storage capacity, which severely hamper the development of PCMs technology. As a means of addressing these challenges, we developed one novel support material with 2D/0D structure for palmitic acid via thermal polymerization, specifically, in which highly dispersed Ag quantum dots (Ag QDs) was firmly anchored on graphitic carbon nitride (g-C 3 N 4). PA was further infiltrated into the layered structure of nanoporous g-C 3 N 4 /Ag QDs to successfully synthesize novel shape-stabilized PA/g-C 3 N 4 /Ag QDs composite phase change materials (CPCM). On the one hand, benefiting from the tightly stacked porous structure of g-C 3 N 4 /Ag QDs, PA is effectively encapsulated to avoid leakage problem during the solid-liquid transition with a superior adsorption capacity up to 65 %. On the other hand, the combination of g-C 3 N 4 and Ag QDs in PA/g-C 3 N 4 /Ag QDs CPCM demonstrated a synergistic effect resulting in faster heat transfer capability and more efficient solar energy capture capability compared to pure PA, which is capable of dual utilization of heat and solar energy. The newly developed PA/g-C 3 N 4 /Ag QDs CPCM features a high melting latent heat and an appropriate phase change temperature, which are 128.35 J/g and 61.92 °C, respectively. The corresponding solidification enthalpy and temperature are 121.70 J/g and 60.02 °C. The photo-thermal conversion efficiency of the material is improved to 78.6 %, facilitating a rapid capture and storage of solar energy. Furthermore, through the optimization of the preparation process, Ag QDs are densely anchored on the surface of g-C 3 N 4 , which retains the excellent properties of metallic silver while eliminates the metal agglomeration phenomenon after repeated utilization of CPCMs. PA/g-C 3 N 4 /Ag QDs CPCM is proved to be extremely recyclable and thermally stable after massive thermal cycles. This innovative and operational encapsulation modified method significantly optimizes the practicality of phase change materials. The obtained shape-stabilized PA/g-C 3 N 4 /Ag QDs CPCM is more versatile, and its unique comprehensive properties can provide high-quality materials for photo-thermal storage systems. • 2D/0D structure g-C 3 N 4 /Ag QDs are constructed to encapsulate PA. • Novel PA/g-C 3 N 4/ Ag QDs CPCM is developed with outstanding and stable thermochemical properties. • PA/g-C 3 N 4 /Ag QDs CPCM exhibits stronger photo-capture capability with increased photo-thermal conversion efficiency of 78.6 %. • By the optimized synthesis process, CPCM has outstanding shape and structural stability to overcome metal agglomeration. [ABSTRACT FROM AUTHOR]

With the increasing demand for highly integrated circuits to optimize energy efficiency, reduce weight, and improve mechanical properties, finding a Magnesium (Mg) matrix material with excellent mechanical strength and high thermal conductivity poses a significant challenge. In this work, titanium (Ti) particles were introduced into AZ91 (Mg-9Al-1Zn) alloy to fabricate Ti/AZ91 composites, employing a combination of stir casting, extrusion and rolling processes. This strategy simultaneously enhances the mechanical properties and thermal conductivity of the Ti/AZ91 composites compared with AZ91 alloy. The incorporation of Ti particles serves to refine grains, expediting the formation of Mg 17 Al 12 phase within the Mg matrix. Optimal comprehensive mechanical properties are attained in 10 wt% Ti/AZ91 composite, exhibiting an ultimate tensile strength of 365 MPa, an elongation of 11.9 %, and a significantly low wear rate of 4.548×10−3 mm3/m. Notably, the 10 wt% Ti/AZ91 composite shows a 41.1 % reduction in wear rate relative to the AZ91 alloy, attributed to the incorporation of hard Ti particles. Furthermore, the thermal conductivity of the 2.5 wt% Ti/AZ91 composite exhibits a significant enhancement over that of the AZ91 alloy. Detailed discussions are provided on the fundamental mechanisms responsible for strengthening, wear resistance, and thermally conductive in Ti/AZ91 composites. These results highlight the substantial potential of Ti/AZ91 composites for lightweight structural applications, such as highly integrated circuits requiring excellent mechanical properties and high thermal conductivity. [Display omitted] • The 10Ti/AZ91 composite demonstrates a remarkable improvement in UTS, EL and wear resistance. • Enhanced mechanical properties results from the deformable Ti particles, refined grains, and weakening of texture. • The Ti/AZ91 composites possess exceptional thermal conductivity while maintaining high strength. [ABSTRACT FROM AUTHOR]

Spark plasma sintering (SPS) shows great potential in the fabrication of bulk YH 2- x. For the first time, the high-pressure SPS (HPSPS) of YH 2- x is explored and compared with the routine SPS. It is found that HPSPS remarkably reduces the densification temperature, and thus the thermal dehydrogenation phase transition (δ-YH 2- x → α-Y) and the hydrogen loss of YH 2- x can be avoided. Nearly fully dense δ-YH 1.80 monolith is successfully prepared by HPSPS under 500 MPa at a relatively low temperature of 800 °C. HPSPS is effective in overcoming the thermal dehydrogenation problem during the sintering of YH 2- x. Compared with significant grain growth in the routine SPS, the grain growth in the HPSPS is very limited. In terms of thermal properties, the thermal conductivity of HPSPS prepared YH 2- x is relatively low below 600 °C, then tends to be closed above 600 °C, compared with routine SPS prepared and directly hydrided YH 2- x. The thermal expansion of HPSPS prepared dense YH 2- x is basically consistent with that of directly hydrided bulk. This study provides a valuable reference for the sintering of high-quality δ-YH 2- x and other metal hydrides monoliths. • High-pressure SPS (HPSPS) is used to fabricate dense δ-YH 2- x for the first time. • The differences between routine SPS and HPSPS of dense YH 2- x are clarified. • HPSPS provides a "low-temperature sintering" and very limited grain growth. • The thermal dehydrogenation problem in the sintering of YH 2- x is overcome by HPSPS. [ABSTRACT FROM AUTHOR]

SiC is a promising structural material for future advanced nuclear energy systems. However, the inherent brittleness and difficulty of densification of SiC limits its practical application. In this study, medium entropy alloy (CrCoNi) reinforced silicon carbide composites (CCN/SiC) were sintered at 1950–2200°C by spark plasma sintering (SPS). The influence of CCN addition on the CCN/SiC composites was investigated in terms of microstructure, mechanical and thermal properties. The results show that SiC sintered at 2200℃ has the highest density, and the addition of 7.5 wt% CCN can significantly improve the fracture toughness of SiC. Transgranular fracture, crack deflection, and premature crack termination due to interfacial passivation are considered as potential toughening mechanisms. Although the addition of CCN can degrade the thermal conductivity of SiC ceramics, it has little effect on the structural stability of the SiC matrix at high temperatures. • A dimpled fracture feature was found in the CCN/SiC composites. • The composite exhibits very good structural stability at 1200 °C. • The addition of CrCoNi doubled the fracture toughness of SiC ceramics. [ABSTRACT FROM AUTHOR]

In the pursuit of advancing the aerospace application of carbon fiber-reinforced aluminum matrix (CF/Al) composites, achieving a balance between strength, toughness, and a reduced coefficient of thermal expansion (CTE) is imperative. This research introduces a novel approach to fabricating a carbon fiber-reinforced titanium/aluminum (Ti-CF/Al-Ti) sandwich composite using a liquid-solid infiltration extrusion method. The microstructure, mechanical properties, thermal deformation, and corrosion resistance were thoroughly analysed. The results show that a 10 μm wide transition layer interface (Al 3 Ti) generated by Ti/Al interdiffusion is formed in the sandwich composite and forms an inlay structure with carbon fibers. Compared with CF/Al composites, the tensile strength of this sandwich composite was enhanced by 137.04% and 207.55% in the axial and radial directions of the fibers, respectively, while the compressive strength was also significantly increased. Notably, the CTE of the sandwich composite in the radial direction of the fibers was reduced by 51.2% after the introduction of the TC4, while the axial CTE remained unchanged. Additionally, the corrosion current density (i corr) exhibited a remarkable decrease by two orders of magnitude, indicating a substantial improvement in corrosion resistance. These findings provide valuable insights into the preparation of CF/Al composite and their applications in aerospace. • Interlocking structure interface enhances load transfer efficiency. • The tensile strength of Sandwich composites was increased by 137.04%. • The transition layer interface retards crack propagation and enhances toughness. • The radial CTE decreased by 51.2%, while the axial CTE remained unchanged. • The i corr exhibited a remarkable decrease by two orders of magnitude. [ABSTRACT FROM AUTHOR]

In this work, (Mg 1/3 Nb 2/3)4+ cationic substitution in lead-free polycrystalline Na 0.5 Bi 0.5 TiO 3 (NBT) has been adopted to synthesize by the conventional solid-state reaction method. The cationic substitution was introduced into NBT through compositional modification, which significantly restricted grain growth and promoted a ferroelectric to relaxor ferroelectric phase transition. The substitution of (Mg 1/3 Nb 2/3)4+ influenced the crystal structure, ferroelectric, dielectric properties, and micromorphology, which had been investigated systematically. The enhancement of relaxor nature is found with this substitution and further verified by dielectric curve, polarization (P) - electric field (E) hysteresis loop, and current (I)- electric field (E) curve. The recoverable energy density was determined to be 1.09 J/cm3 and 1.24 J/cm3 at 101 kV/cm and 114 kV/cm in the 10 mol% and 20 mol% of (Mg 1/3 Nb 2/3)4+ substituted systems, respectively. Furthermore, over the 35 ˚C to 490 ˚C temperature range, the 30 mol% (Mg 1/3 Nb 2/3)4+ substituted composition showed superior thermal stability in the permittivity. Therefore, this study concluded that these cationic substituted NBT compositions are appropriate materials for applications involving higher-temperature and energy storage in electronic devices. • Recoverable energy storage density (W rec) ≈ 1.24 J/cm3 obtained in the 20 mol% with the efficiency of 54 %. • The introduction of (Mg 1/3 Nb 2/3)4+decreases the grain size and improve BDS to improve W rec. • Thermal stability increases in the 35- 490 ˚C temperature range, in the 30 mol% (Mg 1/3 Nb 2/3)4+composition. [ABSTRACT FROM AUTHOR]

At room temperature, monoclinic In 2 W 3 O 12 ceramics exhibits positive thermal expansion. However, it transforms into an orthorhombic phase above 253 ℃, and then stably exhibits negative thermal expansion (NTE). In this work, to improve the NTE performance and extend the NTE temperature range of In 2 W 3 O 12 , the K x Mn x In 2-x W 3 O 12 (0≤x≤0.5) ceramics were synthesized via the solid-state reaction method. The effects of (KMn)3+ double cation co-doping on the composition, microstructure, and thermal expansion behaviors of In 2 W 3 O 12 ceramics were studied using XRD, Raman, XPS, SEM, and TMA. The results show that (KMn)3+ cations can replace In3+ in In 2 W 3 O 12 ceramics. As the (KMn)3+ doping amount increases, monoclinic In 2 W 3 O 12 gradually changed into monoclinic K x Mn x In 2-x W 3 O 12. Meanwhile, the grains grow up and the density of K x Mn x In 2-x W 3 O 12 ceramics was increased. Pure monoclinic K x Mn x In 2-x W 3 O 12 ceramics were prepared when x rises to 0.25 and 0.4. Among them, the thermal expansion coefficient of K 0.4 Mn 0.4 In 1.6 W 3 O 12 ceramics in 100–700 ℃ is as high as -17.83×10-6 ℃-1, which was significantly improved compared to In 2 W 3 O 12 ceramics. In addition, the structural phase transition of In 2 W 3 O 12 ceramics around 253 ℃ was gradually eliminated and the NTE temperature range was widened. Double cation (KMn)3+ co-doping effectively improves the NTE performance of In 2 W 3 O 12. • (KMn)3+ co-doped In 2 W 3 O 12 ceramics were prepared by solid-state method. • (KMn)3+ co-doping induces a phase transition in In 2 W 3 O 12 ceramics. • Monoclinic K x Mn x In 2-x W 3 O 12 ceramics show stronger NTE as x increases. [ABSTRACT FROM AUTHOR]

Aiming at the development of thermal environmental barrier coatings (TEBCs) material, the factor of grain size is introduced into the high-entropy rare-earth disilicate for the first time. The (Yb 0.2 Tm 0.2 Lu 0.2 Sc 0.2 Er 0.2) 2 Si 2 O 7 with smaller grain size was prepared by one-step pressureless sintering method. Results of thermal conductivity and coefficient of thermal expansion (CTE) reveal that thermal conductivity of (Yb 0.2 Tm 0.2 Lu 0.2 Sc 0.2 Er 0.2) 2 Si 2 O 7 bulk material is lower than that all existing EBCs and even most TBCs and potential TEBCs material, which is 0.686 W m−1 °C−1 at 1300 °C. Excellent thermophysical properties indicate that designed (Yb 0.2 Tm 0.2 Lu 0.2 Sc 0.2 Er 0.2) 2 Si 2 O 7 with small grain size can be used as a promising TEBCs material. • It is the first time to introduce the grain size into the thermal conductivity of high-entropy rare earth silicate materials. • The prepared (Yb 0.2 Tm 0.2 Lu 0.2 Sc 0.2 Er 0.2) 2 Si 2 O 7 has very low thermal conductivity than all existing EBCs materials. • (Yb 0.2 Tm 0.2 Lu 0.2 Sc 0.2 Er 0.2) 2 Si 2 O 7 with small grain size has excellent thermophysical properties and is a candidate for TEBCs. [ABSTRACT FROM AUTHOR]

The limited efficiency of traditional trial-and-error experiments has impeded the development and application of high-entropy fluorite oxides in thermal insulation coatings. To solve this problem, a novel entropy descriptor based on first principles is presented to help select candidate components for synthesizing high-entropy fluorite structure oxides. Results show that the compatibilities of 10 single-phase high-entropy fluorite oxides can be accurately predicted based on entropy formation ability. In the studied (Zr, Hf, Pr, La, X) O 2-δ system, a correlation between thermal characteristics and size/mass differences was established by designing the size and mass of X. Specifically, we found that the thermal conductivity is more strongly correlated with the difference in atomic mass, while the coefficient of thermal expansion is strongly correlated with the difference in atomic size. X-ray photoelectron spectroscopy (XPS) analysis shows that the concentration of oxygen vacancy can effectively reduce the thermal conductivity of high-entropy fluorite oxides. In addition, the values of hardness, elastic modulus and thermal conductivity of five single-phase fluorite oxides are successfully predicted by first principles calculation, and the differences between these values and the experimental results are small, which provides a prospective significance for the performance prediction of high-entropy fluorite oxides. Our findings provide a strategy for customizing high-entropy fluorite single-phase oxides with suitable properties to meet the performance requirements of thermal barrier coatings (TBCs). • The DFT calculation provides an entropy descriptor to evaluate the comfiability of high-entropy single-phase fluorite oxides based on their entropy formation capacity. • The hardness, elastic modulus and thermal conductivity of the studied sample are obtained by DFT calculation, and the difference between them and the experimental values is small. • In the (Zr, Hf, Pr, La, X)O 2-δ system, the atomic size difference and atomic mass difference of five single-phase samples were quantified, and their thermal conductivity and thermal expansion values were correlated. [ABSTRACT FROM AUTHOR]

In this work, Cu-1.5 wt%Y (Cu-Y) and Cu-0.75 wt%Y-0.75 wt%La (Cu-Y-La) were prepared by mechanical alloying combined with spark plasm sintering and hot rolling, followed with annealing at different temperatures. The effects of the introduction of La and annealing temperatures on the microstructures, mechanical properties, electrical conductivity and thermal stability of Cu-Y alloys were investigated. Both Cu-Y and Cu-Y-La obtain the heterogeneous mixed grain structures composed of coarse grains and fine grains, and oxide nanoparticles are uniformly dispersed in Cu matrix. With the introduction of La, the grains and oxide nanoparticles are refined, and LaYO 3 nanoparticles with the coherent interfacial structure can be observed in Cu-Y-La. After annealing at 500 ℃, both Cu-Y and Cu-Y-La obtain the most excellent comprehensive tensile properties and highest electrical conductivity (63 %IACS for Cu-Y and 62 %IACS for Cu-Y-La). Benefited from effectively enhanced grain boundary strengthening and particle strengthening mechanisms induced by the combination effect of La and Y, Cu-Y-La shows higher strength than that of Cu-Y (after annealing at 500 ℃, 244 MPa of yield strength for Cu-Y and 300 MPa for Cu-Y-La). Meanwhile, benefited from improved dynamics stability of the Cu matrix induced by significantly refined precipitates and the formation of LaYO 3 nanoparticles with the coherent interfacial structure after introducing La, the better softening resistance is achieved by Cu-Y-La in comparsion with Cu-Y, and almost 100 ℃ improvement of the softening temperature is achieved (966 ℃ for Cu-Y-La and 870 ℃ for Cu-Y). • A novel system of Cu-Y-La alloy for the field of ITER is designed and prepared. • Effects of heat treatment on microstructure and properties of Cu alloys reinforced by rare earth elements are studied. • The significant improvement of mechanical property of Cu-Y alloy is achieved through the combination effect of Y and La. • The softening resistance of Cu-Y alloy is successfully improved through the combination effect of Y and La. [ABSTRACT FROM AUTHOR]

While extensive research has explored Cu doping in n -type Bi 2 (Te,Se) 3 for its beneficial effects on reproducibility and mobility, its impact on p -type (Bi,Sb) 2 Te 3 remains incompletely understood. Recently, Saglik et al. demonstrated Cu 2.9 Te 2 incorporation into Bi 0.5 Sb 1.5 Te 3 as a novel approach for simultaneous Cu doping and intercalation, surpassing prior studies focused solely on Cu doping at Bi/Sb sites. The influence of additional Cu intercalation on both electronic band parameters (density-of-states effective mass, deformation potential, and weighted mobility) and phonon scattering by point defects has yet to be investigated. Here, we employ the Effective Mass model to comparatively assess the impact of Cu intercalation on these band parameters relative to single Cu doping. Furthermore, the Callaway-von Baeyer and Debye-Callaway models are employed to evaluate the effect of Cu intercalation in scattering phonons. Our findings reveal that additional Cu intercalation effectively suppresses the lattice thermal conductivity of Bi 0.5 Sb 1.5 Te 3 to the amorphous limit, offering the potential to improve the figure-of-merit (zT) to ∼2.0 near 420 K with optimized carrier concentration. This approach highlights Cu intercalation as a readily applicable and powerful tool for maximizing the thermoelectric performance of Bi 2 Te 3 -based materials. • Incorporating Cu 2.9 Te 2 into p -type (Bi,Sb) 2 Te 3 makes Cu intercalation possible. • Cu intercalation increases effective mass more effectively than Cu doping. • Cu intercalation suppresses lattice thermal conductivity down to the amorphous limit. • Cu intercalation with optimized carrier concentration can improve the zT to ∼2.0. [ABSTRACT FROM AUTHOR]

Stabilizing the phase structure is the prerequisite for obtaining excellent properties of film materials. Here, we construct a multi-layer superlattice structure including high-entropy sublayer to further tailor the structure and properties of Al-containing nitride coating. A fully cubic structure of Ti 0.11 Nb 0.14 Ta 0.13 Zr 0.14 Si 0.09 Al 0.39 N/Ti 0.55 Al 0.45 N (HEN_M) multilayer is realized by stabilizing the cubic/wurtzite-mixed Ti 0.11 Nb 0.14 Ta 0.13 Zr 0.14 Si 0.09 Al 0.39 N (HEN) sublayers with the cubic Ti 0.55 Al 0.45 N template layers. The coherent interface strain increases the hardness to 37.5 ± 1.1 GPa for HEN_M in comparison with the corresponding monolithic coatings with 28.2 ± 0.9 GPa for Ti 0.55 Al 0.45 N and 22.2 ± 0.7 GPa for HEN. Simultaneously, the HEN_M multilayer shows the optimal Vickers indentation toughness. All coatings exhibit age-hardening characteristics stemming from the spinodal decomposition. Compared to Ti 0.55 Al 0.45 N reaching its peak hardness of ∼32.9 ± 0.9 GPa at 900°C, the sluggish diffusion effect promotes HEN and HEN_M maintaining the maximum hardness of ∼25.6 ± 0.8 GPa and ∼39.6 ± 0.9 GPa upon annealing to 1100 and 1000°C, respectively. In addition, exposed to synthetic air at 850°C for 10 h, Ti 0.55 Al 0.45 N coating has been completely oxidized, whereas the HEN and HEN_M coatings only experience partial oxidation with oxide scales of ∼1.52 and 0.78 μm. • TiNbTaZrSiAlN/TiAlN (HEN_M) realizes the epitaxial growth with coherent interfaces. • HEN_M behaves higher hardness and toughness than corresponding monolithics. • HEN_M presents the peak hardness of ∼39.6 ± 0.9 GPa at 1000°C. • HEN_M achieves optimally elevated oxidation resistance. [ABSTRACT FROM AUTHOR]

Taking inspiration from the unique hierarchical structure of bio-materials like pearl oyster, this study employs bio-inspired composites technological route using flake powder metallurgy to prepare laminated Cu/Ti 3 SiC 2 /C composites. The prepared composites have clear laminated structure, uniform dispersion of reinforcing phase and clean interface. At a Cu-plated GNPs content of 0.5 wt%, the composites displayed tensile strength of 300.65 MPa, compressive strength of 575.32 MPa, electrical conductivity of 26.31 MS/m, and thermal conductivity of 285.87 W·m−1·K−1. The reinforcement of composites is caused by the load transfer effect of the laminated structure. During the loading process, the laminated structure creates multiple paths for deflecting cracks, which leads to the redistribution of the applied load. Moreover, the homogeneous distribution of GNPs throughout the laminated structure extends the mean free path of both free electrons and phonons within the material, consequently bolstering the electrical and thermal conductivity of the composites. [Display omitted] • Cu/Ti 3 SiC 2 /C laminated composites with balanced strength-toughness and good thermal and electrical conductivity were prepared. • The role of the lamellar structure was discussed. • The interfacial reactions and interfacial structure of Cu/Ti 3 SiC 2 /C was investigated. • The study investigated the mechanisms of interfacial thermal conductivity, interfacial electrical conductivity, and reinforced toughening. [ABSTRACT FROM AUTHOR]

This study explores the use of copper foam (CF) as a thermally conductive scaffold for phase change materials (PCMs), enhancing shape stability. Employing the ice template method (ITM), we fabricate a CF with a low-density, honeycomb structure and anisotropy from flake copper powders. The resulting phase change composites (PCCs), infused with paraffin wax (PW), showcase high thermal conductivity and shape retention compared to pure PW, with anisotropic heat flow due to directional channels in the CF. With a 34.4 wt% filling ratio, the PCCs achieve axial and lateral thermal conductivities of 2.85 W m−1 K−1 and 1.51 W m−1 K−1, respectively, and a thermal storage enthalpy of 158.18 J g−1. This work presents a novel method for advanced thermal energy storage and management, indicating the promise of ITM-derived CF in high-performance PCCs for diverse applications. • 3D porous copper with lighter weight, honeycomb-like and directional structure was prepared. • The composite has good form-stability and anti-leakage property. • The composite indicates high thermal conductivity of 2.85 W m−1k−1. • The composite indicates heat storage capability of 158.18 J g−1. • The composite has good anisotropic thermal conductivity. [ABSTRACT FROM AUTHOR]

In this study, the influences of thermal exposure on the microstructure and creep resistance of matrix alloy and (TiB+TiC+Y 2 O 3)/α-Ti composites were systematically studied. The results indicate that long-term thermal exposure leads to β-Ti dissolution, as well as the precipitation of a large number of S1 type silicides and α 2 particles. The high temperature and internal stress by thermal exposure promote β-Ti→α-Ti phase transition. In order to reduce the total energy, nanoscale {10 1 ̅ 1} transformation twins were formed at the α/β interfaces. The introduction of precipitates and nano twins leads to a significant improvement in the creep resistance after thermal exposure. The creep life can be increased by up to 108 %, while the steady-state creep rate can be reduced by an order of magnitude. After creep, there was no significant increase in the size of precipitated silicides and α 2 particles. The rod-shaped S1 type silicide has a better pinning strengthening effect on dislocations than spherical S2 type silicide. Nano twins improve the stability of the α/β interfaces during creep. Some twins were coarsened after creep by merging mechanism. Twins and reinforcements provide nucleation sites for sub-grains during the creep process. • The characteristics of α 2 phases, silicides and nano twins after thermal exposure were investigated. • The reasons for the enhanced creep properties by thermal exposure were analyzed. • The response of silicides and nano twins to creep deformation were analyzed by TEM and HRTEM. • Dynamic recrystallization behavior based on DDRX and CDRX process were discussed. [ABSTRACT FROM AUTHOR]

Sinnerite Cu 6 As 4 S 9 has been identified as a promising material for optoelectronic applications, with potential for other energy-related applications; however, knowledge of the electrical and thermal properties as well as the mechanisms underlying transport in sinnerite is lacking. We present an investigation of the synthesis, structural, thermal and electrical transport properties of stoichiometric and Sn-doped Cu 6 As 4 S 9. Sinnerite has a triclinic lattice structure, with highly distorted local atomic coordination environments that, in part, results in its complex structure and bonding. Our results and analyses indicate As 4 s 2 lone pair-induced distortions and strong lattice anharmonicity that leads to a relatively short phonon mean free path, resulting in intrinsically very low thermal conductivity. The electrical resistivity for both compositions, Cu 6 As 4-x Sn x S 9 (x = 0, 0.2), are relatively high and varies little with temperature, typical of degenerate semiconductors. An increase in mobility and electrical conductivity was obtained by Sn doping in Cu 6 As 3.8 Sn 0.2 S 9. This work demonstrates an effective route to synthesize bulk sinnerite as well as advances the knowledge of the properties of sinnerite, as this and other ternary chalcogenides continue to be of interest for potential technologically significant applications. [Display omitted] • Polycrystalline sinnerites were successfully synthesized by ball milling and solid-state annealing. • The thermal conductivity is intrinsically low (< 1 Wm−1K−1) due to the unique structure and bonding. • The mobility and electrical conductivity increase and the thermal conductivity decreases with Sn doping. • The thermoelectric properties improved by 60% with Sn doping. [ABSTRACT FROM AUTHOR]

Pyrochlore ceramics with chemical formula A 2 B 2 O 7 (A= rare earth, B= tetravalent metal) have extremely low thermal conductivities (κ) and are thought to be promising candidates for thermal barrier coatings (TBCs) applications. This study reports κ for nanocrystalline (nc) Gd 2 Ti 2 O 7 pyrochlore fabricated by spark plasma sintering followed by sintering at different temperatures to better understand their thermal properties. The structural analysis confirmed the synthesis of single-phase nc-Gd 2 Ti 2 O 7 pyrochlore. The thermal conductivity investigations displayed a systematic decrease in thermal conductivity from 1.6 Wm−1K−1 to 0.6 Wm−1K−1 for the sample sintered at a lower temperature due to high porosity. The value of the κ is found to decrease sublinearly (κ ∝ T-α, where 0 < α < 1) with temperature for all the nc-Gd 2 Ti 2 O 7 pyrochlore samples. DFT- GGA calculation exhibits that the nc-Gd 2 Ti 2 O 7 is a direct band gap at the Γ point of the Brillouin zone, and its value is increased with the sintering temperature. In addition, the effect of sintering temperature on the specific heat capacity (C p) is insignificant in nc-Gd 2 Ti 2 O 7 structures, as confirmed by the quasi-harmonic approximation. Theoretical and experimentally determined results are in good agreement, and values are compatible with the thermal insulation requirements for various applications. • The thermal conductivity (κ) decreases from 1.6 Wm-1K-1 to 0.6 Wm-1K-1 with lowering sintering temperature. • The thermal conductivity (κ) decreases similarly for the highly dense samples sintered at 1000 ℃ and 1200 ℃. • The κ value decreases sublinearly (κ ∝ T-α, where 0 < α < 1) with temperature for all the nc-Gd 2 Ti 2 O 7 pyrochlore samples. • DFT calculated specific heat capacity (C p) systematically increases with increasing measuring temperature. [ABSTRACT FROM AUTHOR]

Modified C/C composites are promising candidates to the advanced piston of internal engine, pantograph slide plate and rapid-fire gun barrel. To understand the corrosion in the working conditions of these thermal components, cyclic ablations of C/C-SiC-ZrB 2 -ZrC (C/C-SZZ) were carried out in high frequent impacted combustions at different temperatures (700–2300 ℃). Parallel study of AlSi alloy modified C/C-SiC-ZrB 2 -ZrC (C/C-SZZ-AS) which had lower cost was performed synchronously for comparison. Results indicated that the ablation rates of both the composites went down with decreased temperature while C/C-SZZ-AS presented a faster decline. Compared with C/C-SZZ, the pressure infiltrated AlSi alloy matrix of C/C-SZZ-AS raised the conductivity and specific heat capacity but reduced the emissivity, which led to a lower surface temperature and thermal gradient during ablation. And combined with the better plasticity and toughness of the alloy matrix, C/C-SZZ had stronger ablation resistance below 1500 ℃ in the serious thermal shock. At temperature above 1500 ℃, excessive phase transformation of the AlSi alloy matrix caused more defects and strengthened the mechanical erosion. And then the faster consumption of the AlSi alloy resulted in the greatly worsened ablation property of C/C-SZZ at 2300 ℃. • C/C-SiC-ZrB 2 -ZrC was high frequently cyclic ablated at different temperatures. • Pressure infiltrated AlSi alloy improved the ablation property below 1500 ℃. • The alloy matrix elevated the ablation sensitivity to combustion temperature. [ABSTRACT FROM AUTHOR]

Conducting copolymer nanocomposites of thiophene and indole incorporated with silicon carbide nanoparticles [poly (thiophene-co-indole-SiC) (PPSiC)] has been developed by in-situ copolymerization and these nanocomposites were characterized by different analytical techniques. The FTIR peak at 865 cm−1 signifies the successful incorporation of SiC nanoparticles in the copolymer matrix. The intensity of the UV-Vis absorbance of the copolymer nanocomposites increased with the nanoparticle concentrations, and PPSiC7 showed the highest intensity. This was in correlation with its low optical bandgap energy (3.032 eV) and high refractive index (2.388) value. XRD revealed the consistent positioning of sharp and distinct crystalline peaks of SiC in the copolymer. SEM revealed the effective dispersion of nanoparticles throughout the matrix and uniform dispersion was obtained for PPSiC7 nanocomposite. HR-TEM images validated the presence of spherical-shaped particles in the nanocomposite with the nano-size distribution of SiC. The surface roughness of the copolymer nanocomposite was evident from AFM analysis. TGA and DSC revealed that PPSiC nanocomposites have better thermal properties than the copolymer. AC conductivity increased with frequency and temperature. The PPSiC7 exhibits a maximum conductivity of 1.5×10−2 S/cm at 106 Hz and an activation energy of 0.064 eV. PPSiC nanocomposites demonstrated excellent results in degrading dye and detecting ammonia gas at ambient temperature. All analyses showed that the PPSiC7 nanocomposite exhibited superior properties than the copolymer. These admirable properties can be exploited in developing optoelectronic devices, energy storage devices and gas sensors. • Poly(thiophene-co-indole)/SiC copolymer nanocomposites were synthesized by in-situ copolymerization. • Dye adsorption studies of copolymer nanocomposites were established using methylene blue. • Toxic gas pollutant such as ammonia can be sensed using copolymer nanocomposite-based sensor. • Enhanced optical, thermal, electrical and dielectric properties enables them for used in optoelectronic devices. [ABSTRACT FROM AUTHOR]

The mechanical properties especially the compression performance are very important for thermal interface materials (TIMs) to mitigate warpage failure caused by stress concentration and reduce contact resistance in practical applications. However, high thermal conductivity and excellent mechanical properties are generally incompatible in traditional TIMs. Herein, we fabricate a high-performance carbon fiber-based TIM by using an extrusion method based on the flow shearing effect. The vertically oriented composite shows a through-plane thermal conductivity up to 18.5 W·m−1·K−1 at 20 wt% carbon fiber content, which is 92.7 times that of pure matrix and 6.3 times that of the random structure. Moreover, the as-prepared material exhibits low hardness of 56 (Shore 00) and outstanding elastic compression performance of 51.4% compression under a pressure of 45 psi. These excellent properties are primarily attributed to the high orientation of the carbon fibers (CFs), thereby establishing a direct and effective thermal conductivity path in the vertical direction. In addition, the synergistic effect of carbon fibers and alumina particles is also beneficial for building thermal conduction pathways. Our work provides an insight to further research in fabricating high-performance flexible TIMs as a promising candidate for applying in advanced thermal management fields. • The composite achieves a thermal conductivity of 18.54 W·m−1·K−1. • The composites exhibit good elastic compliance under high through-plane thermal conductivity. • The synergistic effect of carbon fibers and alumina promotes the enhancement of thermal conductivity [ABSTRACT FROM AUTHOR]

The unique transport properties make CuInTe 2 emerge as a promising thermoelectric material. However, the intrinsically low carrier concentration and high lattice thermal conductivity of CuInTe 2 limit its thermoelectric performance. In this work, firstly, we investigate the influence of excess Te on the electrical and thermal transport properties of CuInTe 2. The results suggest that excess Te can act as both electron acceptors and phonon scattering centers, which simultaneously optimizes the carrier concentration and impedes the propagation of high-frequency phonons. Furthermore, the substitutional Ag/Cu defects integrated with excess Te lead to a further reduction in lattice thermal conductivity. DFT calculations indicate that the substitution of Ag for Cu can reduce phonon group velocity and intensify the acoustic phonon scattering, which agrees well with our experimental data. Finally, a high zT value of 1.03 is obtained @840 K for sample Cu 0.8 Ag 0.2 InTe 2.2. This study demonstrates a facile but effective approach to boost the thermoelectric performance of chalcopyrite compounds. [Display omitted] • Excess Te optimizes the carrier concentration and impedes the propagation of high-frequency phonons. • The introduction of Ag on Cu sites results in a further reduction in lattice thermal conductivity. [ABSTRACT FROM AUTHOR]

Thermally conductive, insulating thermal interface materials (TIMs) for solving heat transport problems are facing greater opportunities and challenges than ever before. In this study, a three-dimensional boron nitride (BN)/graphene oxide (GO) skeleton prepared by the ice template method ensures the directional motion of the heat flow. The GO is modified by atom transfer radical polymerisation, so that the GO is connected to the BN through hydrogen bonding and π-π interactions；increases the reaction position of the curing agent with the epoxy group, accelerates the curing reaction of the composite, and synergistically reduce the filler-filler and filler-matrix interfacial thermal resistance. The thermal conductivity of the prepared 3D/BN/GO-EP composites can reach 1.07 W m−1K−1 at a low filler content of 20 wt%, as well as good electrical insulation (volume resistivity 2.59 × 1013 Ω cm) and excellent compression properties (compressible up to 60% of deformation). Meanwhile, Dual Network Co-Transmission Heat Strategy provides a new idea for the research of advanced polymer-based thermal management materials. [ABSTRACT FROM AUTHOR]

This study explores the influence of processing methods on the connectivity of a ceramic component and its effect on the dielectric and thermal properties in Li 2 MoO 4 -polytetrafluoroethylene (LMO-PTFE) composites. Three processing cases were examined: cold sintering (case 1), dry pressing and subsequent thermal annealing (case 2), and cold sintering and subsequent thermal annealing (case 3). The processing methods change the connectivity of ceramic grains, the crystallinity of PTFE, and the dielectric properties of these composites. The microstructure analysis shows that CSP increases the LMO domain size via the dissolution and precipitation steps. The connected LMO grains increases the transport length of Li ions under electric field and manifests the space charge polarization in the dielectric measurments. More connected LMO grains of the composites also enhance thermal transport, while phonon scattering of discrete LMO particles lowers the thermal conductivity of the composites. • Processing methods change the connectivity of a ceramic component in a polymer matrix. • Cold sintering process increases the ceramic domain size in the ceramic-polymer composite. • The connected ceramics grains increase the transport length of Li ions under electric field. • Thermal conductivity can be enhanced by a chain of connected ceramic grains. • This study contributes to the rational design of high-performance dielectric composites. [ABSTRACT FROM AUTHOR]

To improve the incompatibility between thermal conduction and electromagnetic wave absorption properties, 3D interconnected CNF/Co composites as a multifunctional filler were fabricated with magnetic/dielectric dual loss and phonon/electron co-transfer via a straightforward sol-gel and annealing route. Results show that the CNF/Co composites produced at a high Co2+ concentration (c) exhibit low defects, small S BET , large electrical conductivity, and high Co content. The optimal comprehensive properties of CNF/Co composites are achieved at c = 0.8 M. Besides, the CNF/Co composites bear a large thermal conductivity (3.61 W/mK) at a low load (15 wt%) due to the enhanced phonon/electron co-transfer in 3D interconnected CNF frameworks and decreased phonon scattering. Moreover, the CNF/Co composites demonstrate tunable electrical conductivity (σ = 7.53 ×10−5 ∼ 1.22 ×10−2 S/cm) and significant enhancements in electromagnetic wave absorption properties (4.53 GHz/mm, 2.4 mm thickness, 35% load), outperforming most other previously reported materials. The significant enhancements could be attributed to the high attenuation and excellent impedance matching caused by magnetic/dielectric dual-loss Co and 3D interconnected porous frameworks. The exceptional electromagnetic wave absorption properties and thermal conduction endow the 3D interconnected CNF/Co composites with prospective application as a multifunctional filler in modern electronics. 3D interconnected CNF/Co composites were synthesized via a straightforward sol-gel and annealing route, exhibiting a synchronous enhancement in heat conductance and EMW absorption. [Display omitted] • A facile synthesis of 3D interconnected CNF/Co composites. • Optimizing the composition, structure, and properties of the composites. • A synchronous enhancement in heat conductance and EMW absorption. • Revealing the mechanism of synchronous enhancement. [ABSTRACT FROM AUTHOR]

This paper describes high-temperature oxidation behavior and thermal properties of metal-ceramic laminated composites fabricated by spark plasma sintering of Ti 3 Al(Si)C 2 -filled preceramic papers (TAC) and Nb foils. The high-temperature oxidation tests were carried out in air at 800–1300 °C. The phase composition and microstructure of the oxide layers were analyzed by X-ray diffraction and scanning electron microscopy, respectively. The thermal properties were measured by the laser flash method in the temperature range of 30–800 °C. The evolution of the microstructure of the reaction layer (RL) formed at TAC/Nb interfaces was studied. The passive oxidation of the surface TAC layers results in the formation of outer TiO 2 and inner continuous Al 2 O 3 phase at temperatures up to 1100 °C, while local accelerated oxidation occurs above 1100 °C. As a result of breakaway oxidation, a multilayer oxide structure consisting of TiO 2 , Al 2 TiO 5 , Al 2 O 3 and SiO 2 phases were formed. The oxidation of inner Nb layers from the side surface can lead to high volume expansion and generation of stresses in the ceramic and metal layers due to the formation of Nb 2 O 5 oxide phase. The stress relaxation occurred by complex mechanisms, including plastic deformation of the Nb layers, delamination at the interfaces, and formation of cracks in the reaction and TAC layers. The high temperature exposure results in slight increase in columnar grains in the reaction layers at 1200 °C, while the thickness of RL remains unchanged. The TAC/Nb composites exhibit higher thermal conductivity and diffusivity compared to monolithic TAC ceramic composites. • HT air oxidation of laminated Nb/Ti 3 Al(Si)C 2 -TiC composites was studied. • Nb layers significantly affect the oxidation and failure mechanisms of laminates. • Good oxidation resistance of laminated composites up to 1100 °C. • Higher thermal conductivity and diffusivity compared to monolithic composites. [ABSTRACT FROM AUTHOR]

La(Fe,Si) 13 alloys are prone to display burst-like phenomena at their first-order ferromagnetic transition, such as a latent heat decomposed into a succession of heat flux avalanches. For some extreme cases, these phenomena are so pronounced that they can yield recalescence/antirecalescence events. It turns out that these features are also highly sensitive to the technical specificities of the employed measurement systems. Here, we compare the thermal events at the first-order magnetic transition of LaFe 11.4 Si 1.31 Co 0.29 using magnetization, two differential scanning calorimeters and a thermometry probe specially designed for the present study. These techniques are complementary to each other, and allow to make a distinction between the properties influenced by thermal coupling and those more intrinsic to the compound or to the sample. A simple thermal model is built to account for the thermal lags in the different devices, and to provide insights into the dependence of the duration of the transition on the thermal sweep rate. Looking in closer detail at the development of the transition, we found evidence of a rate independent initial regime, followed by a second one along which the same shape of temporal profile is spread over a more or less long duration depending on the sweep rate. Possible underlying mechanisms corresponding to these regimes are discussed. [Display omitted] • Comparative study including rarely considered Tzero DSC and thermometry probes. • A thermal model describes the complex dependency of transition duration on sweeping rate. • Detailed thermometry measurements confirm the reproducibility of the transition path. • A rate independent initial regime is observed from DSCs and thermometry measurements. [ABSTRACT FROM AUTHOR]

Improving thermal properties of polymer-based composites by using different types of fillers most of the time also reduces material elasticity and flexural strength, which is a significant problem for application. To address this problem, we have used two types of two-dimensional materials, such as reduced graphene oxide (rGO) and hexagonal boron nitride (hBN) to achieve better thermal and mechanical properties. Great tensile strength and flexibility of both those 2D-materials combined with good thermal conductivity of hBN provided a synergistic effect for the resulting composites. Here we show the composites with 30% of hBN and 10% rGO by weight that have greatly improved flexural strength and flexural modulus as well as more than threefold increased thermal conductivity as compared to pristine polypropylene. Mechanical properties of composites only filled with hBN are significantly lower. [Display omitted] • Two types of 2D fillers such as hBN and rGO were successfully used in PP matrix. • Usage of two 2D fillers increases thermal and mechanical properties of PP. • Composite with rGO and hBN showed better mechanical properties than with only hBN. [ABSTRACT FROM AUTHOR]

Friction Stir Processing (FSP) involves the use of Silicon Carbide (SiC) and Graphite (Gr) nanoparticles as reinforcements to enhance the properties of AZ91 Mg alloy composites. The relationship between FSP processing parameters and surface properties of Mg alloy composites with SiC and Gr nanoparticles is poorly understood. The present study addresses this and investigates the impact of SiC and Gr volume percentages (%vol), tool traverse speed (TTS), and tool rotational speed (TRS) on the corrosion behavior and microhardness of AZ91 alloy composites. FSP turns graphite into layered graphene, making it more corrosion-resistant and stronger through various strengthening mechanisms. Taguchi optimization yielded optimal settings in runs H7 (1500 rpm-20 mm/min-13 %vol) and H8 (1500 rpm-40 mm/min-7 %vol) for high microhardness and low corrosion rate. Conversely, runs H1 (500 rpm-20 mm/min-7 %vol) and H3 (500 rpm-60 mm/min-13 %vol) resulted in reduced microhardness and increased corrosion rate. Integrating Taguchi and Grey Relational Analysis (GRA) optimized the multi-objective enhancement of microhardness and corrosion resistance, achieving 3rd-level values for TRS, TTS, and %vol. Notably, the reinforcement percentage, followed by TRS and TTS, simultaneously improved these responses. • Fabrication of flawless AZ91 surface hybrid composites using friction stir processing. • Exploring process parameters on the microstructure, microhardness and corrosion behavior. • Strengthening mechanisms associated with microstructural changes and contributions of SiC and Gr reinforcements. • Mechanical exfoliation of few-layered graphene (FLGs) from graphite. • Taguchi-Grey Relational Analysis employed for multi-objective optimization. [ABSTRACT FROM AUTHOR]

The employment of phosphors in luminescence thermometry is deemed one of the pivotal developments in the field. Besides the convenience of remote readings, phosphors may offer a plethora of other alluring benefits in this field. At present, one of the most paramount predicaments in this field involves developing an optical thermometer capable of functioning across an extensive temperature range encompassing hundreds of degrees while simultaneously delivering reasonable thermal sensitivity. As recently proven by us, the range of temperature readout can be significantly enhanced by the combination of intra- and interconfigurational transitions of Pr3+ while maintaining S r > 0.5 %/K across the whole temperature range. In this work, the idea has been extended using the combination of two dopants, Pr3+ and Tb3+, which exhibit minimal interference and instead demonstrate a combined impact of their respective temperature-dependent attributes across a range of almost 850 degrees (17–888 K) with relative thermal sensitivity up to 3.5 %/K at 405 K. Additionally, an impressive value of S r = 1.17 %/K at elevated temperature (738 K) was obtained. Temperature sensing was possible by utilizing both Pr3+ and Tb3+ emissions, showing different thermal quenching properties. That was key for broadening the temperature operating range compared to the singly-doped Y 2 SiO 5 :Pr3+ phosphors. [Display omitted] • Co-substitution of inorganic host structure to broaden temperature operating range. • Y 2 SiO 5 :Pr, Tb as a highly efficient and sensitive luminescence thermometer in the 17–888 K range. • Multiphonon relaxation utilized as a tool to extend the operating range of the luminescence thermometer. [ABSTRACT FROM AUTHOR]

The natural mineral-based CoSbS compound has been identified as a potential candidate material for thermoelectric power generation. In this report, the solid solutions of CoSb 1−x S 1−x Se 2x (x ≤ 0.2) were constructed, and their electrical and thermal properties were studied at the temperatures ranging from 323 to 823 K. The results show that the dual doping of Se on Sb and S sites not only tunes the carrier concentration but also modifies the electronic structure, thereby optimizing the power factor of CoSbS effectively. Meanwhile, both the mass and the strain field fluctuation caused by the substitution of Se for both Sb and S strongly suppress the thermal conductivity of CoSbS, and finally make an enhanced zT ∼0.3 for CoSb 0.8 S 0.8 Se 0.4 at 823 K. In particular, the maximum averaged zT from 323 to 823 K in this study reaches ∼0.2, far exceeding the results of Se doping at single Sb or S site in CoSbS. These results indicate that dual doping at Sb and S sites via Se is an effective approach to make better thermoelectric performance for CoSbS. • Thermoelectric compound CoSbS with dual defects of Se Sb and Se S was constructed. • The carrier concentration and electronic structure of CoSbS were modified effectively by introducing of Se Sb and Se S defects. • An enhanced zT avg was obtained for CoSbS with Se Sb and Se S defects. [ABSTRACT FROM AUTHOR]