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This study is a continuation of our previous work. It aims to characterize the tribomechanical and tribochemical behaviors of Ti3SiC2 in low-viscosity liquids. We found an interesting phenomenon in which the flowing and nonflowing states of ethanol are related to the tribological behavior of Ti3SiC2. Low friction and wear were obtained in flowing ethanol, which is due to the lubrication of the products of tribochemical reactions, especially the oxide scales on worn surfaces. Friction and wear are worse in nonflowing ethanol than in flowing ethanol, with a complicated evolution of coefficient of friction and high wear rate. Three stages of a tribo-oxidation evolution process contribute to the complicated evolution of the coefficient of friction. First, the formation of oxide scales contributes to low friction. Second, the breakup of oxide scales results in an abrupt increase in the coefficient of friction. Finally, scratches and abrasive wear from cumulated debris in nonflowing ethanol lead to a continuous increase in friction and wear. [ABSTRACT FROM AUTHOR]

The tribological behavior of self-mated TiSiC in low viscosity fluids, that is, water and ethanol, is investigated. The results show that both water and ethanol effectively reduce the friction and wear of self-mated TiSiC. The friction coefficient and total wear rates of TiSiC tribo-pair are 0.82 and 2.17 × 10 mm/N m under dry condition, 0.41 and 6.50 × 10 mm/N m in water and 0.16 and 2.22 × 10 mm/N m in ethanol. As sliding distance is prolonged from 0.5 to 22.9 km, the total wear rates of TiSiC in ethanol can be further reduced. Mechanical wear of TiSiC is partly inhibited in water and greatly inhibited in ethanol. Surface polishing of TiSiC pin and tribochemistry are the two distinct characteristics of self-mated TiSiC in ethanol. The surface film in ethanol is composed of TiO and SiO. Tribo-products in ethanol, that is, silica gel and titanium dioxide, are found. Polycondensation of ethanol by the catalysis of TiO and SiO gives birth to paraffins and olefins. [ABSTRACT FROM AUTHOR]