High temperature tribology of TiAlN PVD coating sliding against 316L stainless steel and carbide-free bainitic steel

1. ABSTRACT Reciprocating sliding wear tests were performed on TiAlN coating against 316L stainless steel and carbide-free bainitic steel at temperatures of 40, 400 and 800 oC. The results indicate that material transfer is more pronounced for the softer stainless steel at lower temperatures but at 800 oC, carbide-free bainite exhibits relatively more material transfer. Friction coefficient of stainless steel increases when temperature increases. However, for carbide-free bainite, there is a reduction in friction coefficient at elevated temperatures. This can be attributed to formation of an easily sheared iron oxide layer at elevated temperatures. In case of stainless steel, generation of a thin tribofilm containing aluminium oxide and oxidised transferred material can protect the TiAlN coating against wear at 800 oC.