Tribological behaviors of bulk Ti3SiC2 and influences of TiC impurities

Highly pure and TiC contain bulk Ti3SiC2 samples were fabricated. The tribological behavior and influence of TiC impurities were experimentally investigated using a low carbon steel disk as the counterpart at room temperature with a relative humidity of 23-25%. The highly pure Ti3SiC2 exhibits a decreasing friction coefficient (0.53-0.09) and an increasing wear rate (0.6-2.5 x 10(-6) mm3/Nm) with the sliding speed increasing from 5 to 60 m/s; the normal pressure, in the range of 0.1-0.8 MPa, also has a complex but relatively weak influence on them. The changes can be attributed to the presence of a frictional oxide film consisting of an amorphous mixture of Ti, Si and Fe oxides on the Ti3SiC2 friction surface. TiC impurities cause both of the friction coefficient and the wear rate to increase remarkably in comparison with the highly pure Ti3SiC2 in the case of higher sliding speed or larger normal pressure due to an interlocking action and the pulling-out of TiC grains.