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Ti3SiC2/Cu composites were prepared using spark plasma sintering technology, and the effect of the velocity–load bivariate on the tribological behaviors of the Ti3SiC2/Cu-45# steel tribo-pair at 800 °C was investigated. The physical change and frictional chemical reaction during the friction process were analyzed based on the morphology characterization and frictional interface phases. The related friction and wear mechanism model was established. The results showed that the influence of velocity and load on the tribological performance of the Ti3SiC2/Cu-45# steel tribo-pair was not monotonically linear. When both the velocity and load were large, the coordinated effect of the two led to a low friction coefficient (0.52). At 800 °C, the velocity mainly affected the exfoliation and re-formation of the oxide film on the wear surface of the Ti3SiC2/Cu-45# steel tribo-pair, while the load affected the extrusion and fragmentation of the oxide film on the wear surface of the tribo-pair. In the friction process, frictional oxidation was the main influencing factor for the formation of the oxide film. When the velocity and load were small, the main frictional oxide consisted of SiO2−x and a small amount of CuO. When the velocity reached 1 m/s and the load reached 3 N, the oxide film was partially broken down and flaked off, and the matrix of the Ti3SiC2/Cu composite was exposed and oxidized, at which time the oxide film was composed of SiO2−x, TiO2, CuO, and Fe2O3. Under the synergistic effect of the velocity–load–temperature field, the friction and wear mechanism of the Ti3SiC2/Cu-45# steel tribo-pair changed from abrasive wear to frictional oxidation wear with the increase in velocity and load. [ABSTRACT FROM AUTHOR]

Frictional behavior of carbide-derived carbon (CDC) coatings on SiC was modified by using MoS 3 as solid lubricants in two forms, i.e. a powder lubricant and a lubricating additive. As the powder lubricant, MoS 3 was unfavorable for the tribological behavior of CDC coatings. Moreover, its friction and wear behaviors were worse than that of MoS 2 . As the lubricating additive, MoS 3 was in-situ prepared within CDC coatings to obtain two kinds of CDC-MoS 3 composites with different microstructures. The CDC-MoS 3 composites showed lower friction than untreated CDC coatings and their tribological behavior was significantly affected by the microstructures. [ABSTRACT FROM AUTHOR]

Ti3SiC2/CaF2 composites were prepared by the spark plasma sintering (SPS) process. Both the microstructure of Ti3SiC2/CaF2 and the influence of test temperature on the tribological behavior of the Ti3SiC2/CaF2 composites were investigated. The synergistic effect of friction and oxidation was evaluated by analyzing the worn surface morphology. The results showed that Ti3SiC2/CaF2 were still brittle materials after adding CaF2, which was in agreement with Ti3SiC2. The hardness, relative density, flexural strength and compressive strength of the Ti3SiC2/CaF2 composites were slightly lower than those of Ti3SiC2, and the addition of CaF2 decreased the decomposition temperature of Ti3SiC2 from 1350 to 1300 °C. Simultaneously, as the temperature of the test increased, the friction coefficient of Ti3SiC2/CaF2 showed a downward trend (from 0.81 to 0.34), and its the wear rate was insensitive. [ABSTRACT FROM AUTHOR]