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With an increasing temperature gradient, the internal stress in composites can cause many problems, such as the plastic yield of the matrix, fracture of the reinforcements, growth of pores in the matrix, and debonding of the interface. The reinforcement particularly affects the internal stress, considerably changing the various properties of the composites. ZrMgMo3O12particle (p)/2024Al composites were fabricated using 5−30 vol. % of a near-zero expansion material, ZrMgMo3O12, as a reinforcement. This was achieved via high-energy milling followed by vacuum hot pressing. The influence of the ZrMgMo3O12 content on the thermal expansion and dimensional stability of the composites was investigated. The results indicated that the large thermal mismatch stress between ZrMgMo3O12 and 2024Al limited the addition of ZrMgMo3O12 to the composites. The composites with 30 vol. % ZrMgMo3O12 failed after solid solution treatment during water quenching. With increasing ZrMgMo3O12 content from 5 to 20%, the coefficients of thermal expansion (CTEs) first decreased and then increased, whereas the dimensional stability of the composites first increased and then decreased. The composites with 10% ZrMgMo3O12 had the lowest CTE of 11.3 × 10–6 °C−1 from − 100 °C to 400 °C, and exhibited dimensional stability from room temperature (RT) to 400 °C. [ABSTRACT FROM AUTHOR]

Previous studies have indicated that hydratable magnesium carboxylate (HMC) exhibits potential as an MgO‐based binder, but its limited medium‐temperature strength has hindered its widespread industrial application. In this study, the incorporation of MgO fumes into castables is intended to react with microsilica to form magnesium–silicate–hydrate (M–S–H), and the synergistic effect of HMC and M–S–H is anticipated to improve the mechanical properties of castables at intermediate temperatures. The effects of MgO fumes on the properties of HMC‐bonded castables were comprehensively investigated. The results demonstrate that incorporating MgO fumes into castable serves multiple functions. The ionized MgOH+ from MgO fumes hinders the hydration process of HMC, prolonging the final setting time from 13 to 98 min and improving the workability of castables. The incorporation of MC‐1100 enhanced mechanical properties at medium temperature due to the synergistic effects of brucite, HMC, and M–S–H. Specifically, the CMOR increased 20% after sintering at 800°C. Furthermore, adding MC‐1100 increases the residual strength rate of castable by 10% compared to those without MgO fumes. This can be attributed to enhanced spinel formation resulting from adding MgO fumes that improves elastic modulus and reduces elastic strain energy generation during thermal shock, thus increasing crack propagation resistance. [ABSTRACT FROM AUTHOR]

The nitrogen-doped graphene (C3N) had special physical and chemical properties, thus it was widely used in various fields, especially as a lithium-ion batteries (LIBs) anode material. However, the electric field was one of the important factors affecting the performance of C3N as an anode electrode material for LIBs. Consequently, in this work, first-principal calculations were adopted to investigate the adsorption and migration properties of lithium ions on C3N surface by electric field. Calculation results show that the C3N monolayer exhibited a narrower band gap (0.0191 eV) and lower diffusion barrier (0.107 eV) under the application of the electric field, and the negative value of the adsorption energy increased by degrees with the increase of the electric field. Bader charge analysis and charge density difference calculations also provided forceful evidence for the ability of C3N to adsorb lithium ions. As a result, our theoretical results demonstrated that C3N should be a new type of anode material for LIBs. [ABSTRACT FROM AUTHOR]

Keggin-type molybdophosphoric acid, molybdophosphoric salt and vanadium incorporated molybdophosphoric salt supported on the modified kaolin (MK) were investigated as redox co-catalysts for the oxidative carbonylation of phenol to diphenyl carbonate (DPC) in the absence of solvent. The 20 wt.% of MnAMPV5 (one kind of vanadium incorporated molybdophosphoric salt) loaded on MK showed the highest catalytic activity with the yield of 24.68% and a TON of 306, while the selectivity amounts to nearly 100% in all the carbonylation reactions. The catalysts were characterized by XRD, BET, XPS and H2-TPR. The reusability study showed that the catalysts were stable and active.

With the rapid industrialization and urbanization, the demand for air quality management is more and more urgent. High temperature dust filtration is one important environmental management technology. Porous ceramics are used as filter materials in the field of high-temperature dust filtration because of their unique advantages such as high filtration efficiency, as well as high temperature stability, particle loss resistance, corrosion resistance and durability. This paper mainly introduced several common preparation techniques of porous ceramics, including the traditional organic foam impregnation method, foaming method, in-situ combustion method, pore-forming method and other new methods such as the template method, gel injection molding method, freeze-drying method, multi-component co-precipitation method and hydrogel method. The principle, advantages and disadvantages of these preparation technologies and their research status were described. The application of these technologies in the field of high temperature dust filtration was briefly reviewed. Finally, the application prospect of the porous ceramics in the field of high temperature dust filtration was prospected. [ABSTRACT FROM AUTHOR]

Ultra-high temperature ceramic coatings have ultra-high melting points, excellent mechanical properties and high temperature ablation resistance. These unique performance combinations turn it into a promising material for use in extreme environment structures in rockets and hypersonic vehicles, particularly nozzles, leading edges and engine components. In this paper, various preparation methods of ultra-high temperature ceramic coatings were reviewed, including plasma spraying, chemical vapor deposition, pack cementation, slurry sintering, hot pressing and their research progress. Meanwhile, some new preparation methods of high temperature coatings, such as ion beam deposition, ultrasonic spraying, metal organic frame work coating, and magnetron sputtering, were introduced. The development trend of ultra-high temperature coatings was prospected as well. [ABSTRACT FROM AUTHOR]

The pyrolytic carbon of polymer adsorbent resin (SAP) is used as a waste carbon source, which can be used as a porous carbon network via pyrolysis to remove surface sodium carbonate and other substances. In this paper, a ZnFe2O4/nitrogen-doped porous carbon composite was prepared using the template method. Through the high-temperature carbonization of a polymer and crystallization of inorganic elements, the morphology of the composite showed uniform load characteristics. This well-defined structure and morphology facilitate the transport of Li+, enhance the effective contact area with the electrolyte, and provide a wealth of active sites. For the SAP-Fe/Zn anode, at a high current density of 0.1 A g−1, the reversible capacity of the anode reached 753 mAh g−1 after 200 cycles, showing excellent magnification performance. The final modified SAP-Fe/Zn&NC electrode had a reversible capacity of 205.6 mAh g−1 after 1000 cycles at the high current density of 2 A g−1, and the cycle retention rate was as high as 80.7%. The enhanced electrochemical performance can be attributed to the abundant active sites and shortened diffusion pathway of the composite. This ensures adequate conversion reactions during the Li-litization process between Zn, Fe, and Li+, alleviates volume expansion, and prevents comminution/aggregation during long cycles at high current densities. [ABSTRACT FROM AUTHOR]

With the increasing application of lithium-ion batteries, the demand for high energy density, high-rate performance and high stability lithium-ion batteries is becoming more and more urgent. Ti 2 CO 2 MXene, as a two-dimensional material with multilayer atomic structure and multiple active sites, has great advantages in lithium-ion battery electrode materials. However, the original Ti 2 CO 2 MXene has been unable to meet the requirements of lithium-ion batteries due to its semiconductor properties. Doping is an effective means to regulate the conductivity and electrochemical properties of Ti 2 CO 2 and improve the capacity of lithium-ion batteries and other energy storage devices. Hence, we use first-principles calculations to study the effect of V atom doping on the adsorption and diffusion of Li on the MXene surface. The density of states (DOS) and partial density of states (PDOS) of TiVCO 2 and Ti 2 CO 2 MXene indicated the transition of their conductive types from semiconductors to conductors. In addition, we observed that TiVCO 2 has higher electrical conductivity and ion transport speed than the original Ti 2 CO 2 MXene, and at the same time, Li atoms can be adsorbed well on the surface of MXene and show a lower diffusion energy barrier. Therefore, TiVCO 2 is expected to become the anode material for the next generation of lithium-ion batteries and has good lithium storage performance., Competing Interests: There are no conflicts to declare., (This journal is © The Royal Society of Chemistry.)