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Based on the discrete element method, this study has simulated the movement of materials in the plated barrel using EDEM software to investigate the effect of the impact medium with different particle sizes on the mechanical deposition plating. The simulation analyzed the interaction between five impact mediums with different particle sizes (2, 3, 4, 5, and 6 mm) and the base body while determining the particle size ratio of the impact medium. The rationality of the particle size ratio was verified by the simulation analysis of the interreaction of two groups of mixed particle size impact medium and the base body. The samples of mechanically deposited zinc coating were prepared. The average thickness, relative density, and average deviation of the coating were measured. The results show that When the particle size is 2 and 3 mm, the effective collision frequency of the materials is higher. When it is 3, 4, and 5 mm, the kinetic energy of collision between materials fluctuates evenly. When it is 4 and 5 mm, the collision contact force of the materials changes regularly. Consequently, the obtained particle size ratio (second group) is 2 mm 23%; 3 mm 23%; 4 mm 23%; 5 mm 27%; and 6 mm 4%. Compared with mixed impact media with 20% of each of the five particle sizes (first group), in the second group of assorted particle size simulation test, the collision frequency between materials is high. The contact force changes more regularly between materials. The average thickness, relative density, and average deviation of the mechanically deposited galvanized layer are consistent with the simulation results of the two groups of mixed particle sizes. The average thickness and relative density of the galvanized layer in the second group are higher, the average deviation is smaller, and the compactness and uniformity are the best. [ABSTRACT FROM AUTHOR]

The main challenge for sodium storage is to find suitable host materials to accommodate larger-sized Na+ and conquer sluggish chemical kinetics. Herein, by adjusting the heat treatment environment, a novel few-layered molybdenum oxide selenide encapsulated in a three-dimensional (3D) N-doped carbon skeleton (MoO3–MoSe2–NC) is rationally constructed to improve the rate performances and cycle life for sodium-ion batteries (SIBs). A small quantity of MoO3 is generated on the edge of MoSe2via in situ local phase transformation by treatment temperature in the air, which effectively regulates the electronic structure, enhances the intrinsic conductivity, and provides more active sites of MoSe2 species. The layered NC acts as a nanoreactor to encapsulate MoO3–MoSe2, which not only effectively improves the conductivity of MoO3–MoSe2, shortens the diffusion pathway of Na+, but also alleviates the volumetric expansion effect of MoO3–MoSe2, playing a key role in providing structural stability for the electrode. Utilizing the phase and interface engineering, the MoO3–MoSe2–NC anode delivers a high specific capacity of 551 mA h g−1 at 0.1 A g−1 upon 150 cycles for SIBs, and a reversible capacity of 368 mA h g−1 is maintained even under 1 A g−1 after 600 cycles. By pairing with commercial Na3V2(PO4)3, this MoO3–MoSe2–NC also exhibits excellent performances in full cells. This study develops a universal interface manipulation strategy for the synthesis of anode materials to boost fast sodium storage kinetics. [ABSTRACT FROM AUTHOR]

Titanium alloys are widely used in various structural materials due to their lightweight properties. However, the low wear resistance causes significant economic losses every year. Therefore, it is necessary to implement wear-resistant protection on the surface of titanium alloys. In this study, four types of in situ composite ceramic coatings with two-layer gradient structures were prepared on a Ti-6Al-4V (TC4) substrate using laser cladding. In order to reduce the dilution rate, a transition layer (Ti-40SiC (vol.%)) was first prepared on TC4 alloy. Then, a high-volume-fraction in situ composite ceramic working layer (Ti-xFe-80SiC (vol.%)) with different contents of Fe-based alloy powder (x = 0, 5, 10 and 15 vol.%) was prepared. The working surface of Ti-40SiC (TL) exhibited a typical XRD pattern of Ti, TiC, Ti5Si3, and Ti3SiC2. In comparison, both Ti-80SiC (WL-F0) and Ti-5Fe-80SiC (WL-F5) exhibited similar phase compositions to the TL coating, with no new phase identified in the coatings. However, the TiFeSi2 and SiC phases were presented in Ti-10Fe-80SiC (WL-F10) and Ti-15Fe-80SiC (WL-F15). It is proven that the addition of the Fe element could regulate the in situ reaction in the original Ti-Si-C ternary system to form the new phases with high hardness and good wear resistance. The hardness of the WL-F15 (1842.9 HV1) is five times higher than that of the matrix (350 HV1). Due to the existence of self-lubricating phases such as Ti5Si3 and Ti3SiC2, a lubricating film was presented in the WL-F0 and WL-F5 coatings, which could block the further damage of the friction pair and enhance the wear resistance. Furthermore, a wear-transition phenomenon was observed in the WL-F10 and WL-F15 coatings, which was similar to the friction behavior of structural ceramics. Under the load of 10 N and 20 N, the wear volume of WL-F15 coating is 5.2% and 63.7% of that in the substrate, and the depth of friction of WL-15 coating is only 14.4% and 80% of that in the substrate. The transition of wear volume and depth can be attributed to the wear mechanism changing from oxidation wear to adhesive wear. [ABSTRACT FROM AUTHOR]

The pursuit of an advanced functional coating that simultaneously combines high hardness, wear resistance, and superior electrical conductivity has remained an elusive goal in the field of copper alloy surface enhancement. Traditional solid solution alloying methods often lead to a significant increase in electron scattering, resulting in a notable reduction in electrical conductivity, making it challenging to achieve a balance between high hardness, wear resistance, and high conductivity. The key lies in identifying a suitable microstructure where dislocation motion is effectively hindered while minimizing the scattering of conductive electrons. In this study, a novel Cu-MoSi2 coating was successfully fabricated on a CuCrZr alloy surface using the coaxial powder feeding high-speed laser cladding technique, with the addition of 10–30% MoSi2 particles. The coating significantly enhances the hardness and wear resistance of the copper substrate while maintaining favorable electrical conductivity. As the quantity of MoSi2 particles increases, the coating's hardness and wear resistance gradually improve, with minimal variance in conductivity. Among the coatings, the Cu-30%MoSi2 coating stands out with the highest hardness (974.5 HV0.5) and the lowest wear amount (0.062 mg/km), approximately 15 times the hardness of the copper base material (65 HV0.5) and only 0.45% of the wear amount (13.71 mg/km). Additionally, the coating exhibits a resistivity of 0.173 × 10−6 Ω·m. The extraordinary hardness and wear resistance of these coatings can be attributed to the dispersion strengthening effect of MoxSiy particles, while the high electrical conductivity is due to the low silicon content dissolved into the copper from the released MoSi2 particles, as well as the rapid cooling rates associated with the high-speed laser cladding process. [ABSTRACT FROM AUTHOR]

In order to ensure the normal operation and safety at work of electronic equipment, the research on thermal management of electronic components has continued increasing in recent years. Graphite film produced with polyimide (PI) as the substrate is an important thermal conductivity material, and its thermal conductivity can be improved through doping modification. Compared with solid thermal conductive filler, ionic liquid has better compatibility with polyimide matrix, and has been commonly used in gas separation membrane, colorless polyimide (CP1) and other applications. This article used 4, 4'-diaminobenzoylanilide (DABA) and 3, 3', 4, 4'-biphenyltetracarboxylic dianhydride (BPDA) as monomers, and modified PI films by using l-ethyl-3-methylimi-dazolium bis[(trifluoromethyl)sulfonyl]imide(lL) that had the characteristic of multiple hydrogen bond sites. Then, high thermal conductivity graphite film was prepared by graphitization. The research results show that when the 1L content is 5.0 wt%, the grain size of the graphite film is 78.417 nm, the degree of graphitization reaches 88%, and the thermal conductivity reaches 770 W/mK, which is 1.53 times that of the pure PI cornerstone ink film. [ABSTRACT FROM AUTHOR]