Oxide-film-dependent tribological behaviors of Ti3SiC2

The tribological behaviors of high pure bulk Ti3SiC2 dry-sliding against a low carbon steel disk were investigated on a block-on-disk type tester under several sliding speeds from 5 m/s to 60 m/s and normal pressures from 0.1 MPa to 0.8 MPa. It was found that both the coefficient of friction and the wear rate of Ti3SiC2 were dependent on the presence of a frictional film consisting of oxides of Ti, Si and Fe in the Ti3SiC2 friction surface. The oxide film was formed and the percentage of coverage was increased with increasing the normal pressure for the medium sliding speeds of 20 m/s and 40 m/s. The oxide film could be formed but was maintained difficultly with increasing the normal pressure when the sliding speed was up to 60 m/s. Few of the oxides was generated and hence almost no oxide film was formed in the friction surface when the sliding speed was 5 m/s. The presence of the oxide film induced the coefficient of friction to reduce, but made the wear rate of Ti3SiC2 increase. The coefficient of friction and the wear rate (×10−6 mm3/Nm) of Ti3SiC2 were of 0.53 and 0.91, 0.26 and 1.35, 0.16 and 2.05, and 0.29 and 3.75 under the normal pressure of 0.8 MPa and the sliding speed of 5 m/s, 20 m/s, 40 m/s and 60 m/s, respectively.