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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]

• A silicate thermal insulation coating was prepared using water glass, etc. • The properties and structures of the coating were analyzed by various methods. • The coating formed a Si-O three-dimensional network structure at high temperatures. • The optimal preparation parameters and thermal insulation efficiency were determined. Thermal insulation slurry was fabricated using sodium silicate water glass (SSWG) as the film-forming material and hollow glass microspheres (HGM) as thermal insulation fillers. The thermal insulation slurry was coated on 316L stainless steel to fabricate a silicate thermal insulation coating. The results show that SiO 2 phase is formed by SSWG in the thermal insulation coating after sintering at 680 ℃. Through polymerization and dehydration reactions between Si-OH groups, the Si-O three-dimensional network structure develops at 680 ℃. The optimal value of SSWG to aggregate mass ratios is 2.00. Under this condition, the silicate thermal insulation coating exhibits smooth surface, continuous and dense microstructure, high Shore hardness of 50.1 HSD, remarkable thermal insulation efficiency of 21 % at 260 ℃, and excellent resistance to drop and thermal shock tests without any noticeable cracks or detachment. [ABSTRACT FROM AUTHOR]

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]

Copper-graphite composites find extensive application as electrical contact materials. However, their tribological properties are limited by the weak interfacial bonding. In this study, Ti 3 AlC 2 was used to modify copper-graphite composites fabricated by vacuum sintering. The incorporation of Ti 3 AlC 2 included both coated Cu and uncoated Cu. The hardness, relative density, tribological properties, and microstructure of the composites were thoroughly investigated. The results show that the addition of Ti 3 AlC 2 coated with Cu was conducive to avoiding the agglomeration of Ti 3 AlC 2 particles, and resulting in superior relative density, hardness, lubrication and wear resistance of the composites. Furthermore, the incorporation of Ti 3 AlC 2 not only enhanced the presence of lubricating components in copper-graphite composites but also improved the interface bonding strength between the copper matrix and graphite. Specifically, Cu-graphite-Ti 3 AlC 2 (Cu-coated) composites displayed a relative density of 92%, a hardness of 94.2 HV, a friction coefficient of 0.175, and a wear rate of 1.28 × 10−6 mm3/N·m. • Graphite and Ti 3 AlC 2 were used to synergistically reinforce copper matrix composites. • The microstructure and properties of Cu-graphite-Ti 3 AlC 2 composites were investigated. • The interfacial bonding between copper and graphite was improved. [ABSTRACT FROM AUTHOR]

Copper/graphite composites and copper/graphite/Ti 2 SnC composites were fabricated through the process of ball-milling, pressing and sintering. The effects of Ti 2 SnC as the second lubrication component on the mechanical properties, wear resistance and lubrication properties of copper/graphite composites were studied in this paper. The results showed that copper/graphite/Ti 2 SnC composites had better hardness, impact toughness, wear resistance and lubrication performance than copper/graphite composites. The optimum values of hardness, impact toughness, friction coefficient and wear rate of copper/graphite/Ti 2 SnC composites were, respectively, 56 HSD, 1.8J/cm2, 0.15, 9.126 × 10−6 mm3/N·m, while these were only 45 HSD, 1.2 J/cm2, 0.17, 3.534 × 10−4 mm3/N·m of copper/graphite composites. [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]

Cu/graphite composites are widely used in various fields as friction materials. However, their tribological properties are limited by the inadequate wettability between Cu and graphite and the insufficient strength of the Cu matrix. To strengthen Cu/graphite composites and improve their interface bonding, this investigation employed Cr 2 AlC to modify Cu/graphite composites fabricated by spark plasma sintering (SPS). The microstructure, interface characteristics, and tribological properties of the composites were thoroughly examined. The results show that the composites exhibit favorable tribological properties, which improved with the increase in sintering temperature. Specifically, as the sintering temperature increases from 800 °C to 980 °C, the friction coefficient of the composites decreases from 0.170 to 0.138, while the wear rate decreases from 9.92 × 10−7 mm3/N·m to 1.86 × 10−7 mm3/N·m. [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]

In this study, a novel mercapto-terminated hexanuclear iron(III) cluster [Fe 6 O 2 (OH) 2 (O 2 CC 6 H 4 SCH 3 ) 10 (hep) 2 ]·CH 3 CN·CH 2 Cl 2 [hep=2-(2-hydroxyethyl) pyridine] (Fe6) modified Au electrode was fabricated, having highly sensitive dopamine (DA) detection capabilities. In such Fe6 molecules, 10 thiomethyl groups are located at the periphery of the cluster, which enable the Fe6 molecules to self-assemble onto the surface of Au electrodes through the formation of Au–S bonds. The as-prepared Fe6-modified Au electrode (Au/Fe6) exhibits excellent electrocatalytic activity for the oxidation of dopamine (DA) in PBS with a diffusion coefficient of 3.12×10 −5 cm 2 /s. Using the square wave voltammetry (SWV) technique, the calibration curve for DA determination was obtained in the range of 0.2 to 30 μM, and the detection limit for DA was ~0.07 μM. Furthermore, the modified electrode can accurately separate the DA signal from the interfering effect of uric acid (UA), thus providing simultaneous detection of DA and UA in their binary mixtures. This electrode can be reliably used to assay DA in its real drug composition. [ABSTRACT FROM AUTHOR]

A new mercapto-terminated binuclear Cu(II) complex, [Cu 2 Cl 2 (mtboc) 2 (C 12 H 8 N 2 ) 2 ] [mtboc =2-(methylthio)benzo[ d ]oxazole-5-carboxylic acid] (Cu2), was synthesized and characterized by single-crystal X-ray diffraction studies. The Cu2 complex was then immobilized on the surface of Au electrodes through S Au bonds to form a self-assembled monolayer. The electrochemical properties of the as-prepared Cu2- modified Au electrode (Au/Cu2) were investigated using cyclic voltammetry, electrochemical impedance spectroscopy, and differential pulse voltammetry (DPV). Moreover, as a biomimetic sensor for the determination of dopamine (DA) and uric acid (UA), the Au/Cu2 electrode exhibited excellent electrocatalytic activity for the oxidation of DA with a faster electron-transfer rate (6.61 s −1 ). The DPV technique was used for the trace determination of DA. The dependence of current vs. concentration was linear from 0.2 to 30 μM with a regression coefficient of 0.9975, and the detection limit of DA was ∼ 0.08 μM. Furthermore, the modified electrode clearly separated the DA signal from the interference effect of UA, thus realizing the simultaneous detection of DA and UA. Finally, the method was applied to the selective and precise analysis of DA in commercial injection and urine samples. [ABSTRACT FROM AUTHOR]