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This research investigates the effects of pack cementation parameters on the thermodynamics, growth kinetics, and microstructure of the simple and silicon‐modified aluminide coatings on the IN718 superalloy. The growth kinetic modelling of the aluminide coating, activated by NH4Cl, is established as h=174252.02T12WAl12WNH4Cl12t12exp-8306.5T ${h={{174252.02}\over{{T}^{{{1}\over{2}}}}}{W}_{Al}^{{{1}\over{2}}}{W}_{NH4Cl}^{{{1}\over{2}}}{t}^{{{1}\over{2}}}exp\left({{-8306.5}\over{T}}\right)}$. further optimizing the kinetics modelling that includes both CaCl2 activator or the mixture of CaCl2 and NH4Cl. The results showed that NH4Cl as an activator generated a higher equilibrium partial pressure of halides, which enhanced the deposition efficiency of active Al atoms and facilitated the significant precipitation of Cr‐rich carbides. Additionally, part of the CaCl2 substitute NH4Cl could maintain a high coating growth rate and reduce the hazards. Adding Si element preferentially combines with Cr formed the Cr9.1Si0.9 phase along grain boundaries, which blocked the inner‐diffusion channels of Al atoms and reduced the thickness of the silicon‐modified aluminide coating compared to simple aluminide coating. These researches revealed the relationship among the thermodynamics, growth kinetics, and microstructure of simple and silicon‐modified aluminide coatings. The thickness and microstructure of coatings can be effectively regulated by adjusting the powder composition, content, and process parameters to achieve precise control. [ABSTRACT FROM AUTHOR]

MoSe 2 -Ag composite films are fabricated by the magnetron co-sputtering method in this study. The effects of Ag concentration on the composition, microstructure and mechanical properties of the films are analyzed by X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, high-resolution transmission electron microscopy and nanoindentation measurements. The results show that the incorporation of Ag during co-sputtering can inhibit the growth of the columnar crystal in the MoSe 2 films. With increasing Ag content, the microstructure of the MoSe 2 -Ag composite films undergoes a structural transformation from a columnar structure to a compact and featureless structure and then to a granular structure. It is confirmed that in the MoSe 2 -30.3 at% Ag composite film, the amorphous Ag phase is diffusely distributed in the MoSe 2 matrix and the addition of Ag does not change the initial chemical state of MoSe 2. The measured hardness of the MoSe 2 -Ag composite films decreases with increasing Ag content. In contrast, the modulus of the films increases with increasing Ag content. A suitable Ag incorporation of 30.3 at% results in relatively comprehensive mechanical properties with a hardness and modulus of 2.2 ± 0.1 and 48.4 ± 2.6 GPa, respectively. • The MoSe 2 -Ag composite films were prepared through magnetron co-sputtering. • The influence of Ag addition on the microstructure transformation is investigated. • The addition of Ag induced a decrease in film hardness but improved its modulus. • MoSe 2 -30.3 at% Ag film shows a compact structure and comprehensive mechanical properties. [ABSTRACT FROM AUTHOR]

• TiC particles in the composites were synthesized by in-situ decomposition of Ti 3 AlC 2. • The interfacial bond strength between the copper matrix and graphite was strengthened through the presence of a TiC layer. • Copper-graphite-TiC composites were analyzed by XRD, SEM and EDS. Copper-graphite-TiC composites were prepared by gas pressure sintering, using copper-coated graphite, pure copper, and Ti 3 AlC 2 as the raw materials. The phase composition and microstructure of copper-graphite-TiC composites have been studied. The results indicate that a strong interdiffusion occurred between the copper matrix and Ti 3 AlC 2 during the sintering process. Ti 3 AlC 2 was completely decomposed into TiC, and a TiC interface transition layer was formed to enhance the bonding strength between the copper matrix and graphite. [ABSTRACT FROM AUTHOR]

Cu-graphite-Cr 3 C 2 composites were synthesized via spark plasma sintering (SPS) using different gas environments, including argon and air, to blend the raw materials consisting of Cr 2 AlC, Cu-coated graphite, and pure Cu. The microstructure and physical properties of the composites were thoroughly investigated. The findings revealed that Cr 3 C 2 , synthesized in situ from Cr 2 AlC, was firmly embedded in the Cu matrix. Additionally, a layer of Cr 3 C 2 was formed at the interface between the Cu matrix and graphite. The composites showed a high relative density, which above 96 %. The composites fabricated with the raw materials mixed in an argon gas environment had a hardness of 72.6 HSD and an electrical conductivity of 1.102 × 106 S·m−1. Whereas, the hardness and electrical conductivity of the composites fabricated with the raw materials mixed in an air gas environment increased to 75.6 HSD and 1.314 × 106 S·m−1, respectively. Furthermore, Cu-graphite-Cr 3 C 2 composites fabricated with the raw materials mixed in air rather than argon exhibited better lubrication performance and wear resistance, the average friction coefficient and wear rate were measured to be 0.4644 and 2.682 × 10−7 mm3/N·m, respectively. • Cu-graphite-Cr 3 C 2 composites were prepared with copper-coated graphite, copper and Cr 2 AlC. • Cr 3 C 2 was synthesized from Cr 2 AlC in situ. • The microstructure and properties of Cu-graphite-Cr 3 C 2 composites were investigated. • The composites samples were analyzed by XRD, SEM and EDS. [ABSTRACT FROM AUTHOR]

Copper/graphite/Ti 2 SnC composites were prepared using spark plasma sintering with copper-coated graphite powder, Ti 2 SnC powder, and copper powder as raw materials. The effect of sintering temperatures (800, 850, 900, and 950 °C) on the microstructure, relative density, hardness, resistivity, and tribological properties of the composites was studied in this paper. The results show that Cu and Ti 2 SnC demonstrate obvious inter-diffusion during sintering and become stronger with an increase in the sintering temperature, and the phase change process of the Cu matrix was in the order: Cu → Cu 5.6 Sn → Cu 41 Sn 11 → Cu 3 Sn. The relative density, hardness, friction coefficient, and the wear rate of the composites were the best when the sintering temperature was 900 °C, and their values were 97.21%, 67.68 HSD, 0.25, and 3.72 × 10−6 mm3/(N·m), respectively, whereas the resistivity of the composites was the best when the sintering temperature was 950 °C, and it was 6.116 × 10−7 Ω m. • Copper/Graphite/Ti 2 SnC composites were prepared by spark plasma sintering. • The composites samples were sintered at different temperatures (800, 850, 900, 950 °C). • The tribological properties, hardness, and resistivity of the composites samples were investigated. • The composites samples were analyzed by XRD, SEM, and EDS. [ABSTRACT FROM AUTHOR]