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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]

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]

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]