The bulk Ti3SiC2 specimens with less than 1 wt% TiC impurity were prepared by vacuum sintering technique, and the average grain size was about 5-6 μm in the elongated direction. When the sintering temperature, soaking time and heating rate were 1 400 ℃, 1 h and 10℃·min-1, respectively, the highest relative density of Ti3SiC2 specimens could reach 97.8%. Meanwhile, the lowest coefficient of friction （COF） and wear rate （WR） of the Ti3SiC2 samples were 0.55 and 1.37×10-3 mm3（Nm）-1 at a sliding speed of 0.35 m/s, load pressure of 10 N and ambient condition, respectively. The COF of the Ti3SiC2 sample reduced with the increasing of the load pressure, while the WRs fluctuated little. The WR increased with the increasing of the sliding speed, and weakly influenced the COF. These changing behaviors could be attributed to the presence and coverage of the amorphous mixture oxide film ofTi, Si, A1, and Fe on the Ti3SiC2 friction surface. The self- antifriction mechanism led to reducing of the COF. The increasing of the WR was attributed to the wearing consumption.
史晓亮ZHAI WenzhengPENG MeichaoZHU ZhiweiWANG MangXU ZengshiYAO JieSONG SiyuanAbid Qamar ud Din
The tribological properties of TiAl-Ti_3SiC_2 composites （TMC） against Si_3N_4 ceramic ball pair at room temperature were investigated through the determination of friction coefficients and wear rates, and the morphologies and compositions of wear debris, worn surfaces of TMC and Si_3N_4 ceramic ball were analyzed. The experimental results showed that TMC with 15wt% Ti_3SiC_2 exhibited relatively excellent tribological properties. The solid-phase self-lubricating tribo-layers formed on the worn surfaces of both TMC with 15wt% Ti, SiC, and Si,NA ceramic ball, which was beneficial to the lower friction coefficient and wear rate.
Tribological behavior of TiAl-multilayer graphene-Ag composites （TMACs） prepared by spark plasma sin- tering against a Si3N4 ball was investigated on a ball-on-disk high-temperature tribometer at different test temperatures and sliding speeds in this study. The test results showed that TMACs had the lower friction coefficient and less wear rate at 450 ℃-0.25 m/s, which was attributed to the formation of the high-strength and intact tribofilms on worn surface. At 450 ℃-0.25 m/s, during the sliding process, multilayer graphene （MLG） was ground out to form the high-strength skeletons on the wom surface of TMACs. Ag was migrated from the worn surface and combined with the MLG skeleton to form the high-strength and intact tribofilms. The high-strength and intact tribofilms were beneficial to lowering the friction coefficient for the lubricating effect of Ag and decreasing wear rate for the enhancing effect of MLG skeleton.
