Tribological behavior of Ti2SC at ambient and elevated temperatures

The tribological properties of Ti2SC were investigated at ambient temperatures and 550 degrees C against Ni-based superalloys Inconel 718 (Inc718) and alumina (Al2O3) counterparts. The tests were performed using a tab-on-disk method at 1 m/s and 3N (approximate to 0.08 MPa). At room temperature, against the superalloy, the coefficient of friction, mu, was similar to 0.6, and at similar to 8 x 10(-4) mm(3).(N.m)(-1) the specific wear rate (SWRs), was high. However, against Al2O3, at similar to 5 x 10(-5) mm(3).(N.m)(-1) and similar to 0.3, the SWRs and mu were significantly lower, which was presumably related to more intensive tribo-oxidation at the contact points. At 550 degrees C, the Ti2SC/Inc718 and Al2O3 tribocouples demonstrated comparable mu's of similar to 0.35-0.5 and SWRs of similar to 7-8 x 10(-5) mm(3).(N.m)(-1). At 550 degrees C, all tribosurfaces were covered by X-ray amorphous oxide tribofilms. At present, Ti2SC is the only member of a family of the layered ternary carbides and nitrides (MAX phases) that can be used as a tribo-partner against Al2O3 in the wide temperature range from ambient to 550 degrees C.