Abstract: The friction and wear properties of mullite-based composites, such as ZTM and ZTM/Al, are dealt with when they wore against TZP ceramics under dry sliding. It is found that the wear rates of ZTM and ZTM/Al ceramics decrease with the increase of temperatures and adhesive layers emerge on their surfaces. The main mechanisms of the formation of adhesive layers are surface diffusion of Zr atoms form TZP to ZTM and ZTM/Al and /or the adsorption of debris on the surface of ZTM and ZTM/Al surfaces during the friction processed. The main factors affecting the Zr atom diffusion are analyzed. The physical and chemical adsorption mechanisms of debris on ZTM and ZTM/Al surfaces are also studied. Therefore, a very important conclusion is that the formation of surface adhesive protective layers on the surfaces of ZTM and ZTM/Al ceramics is the wear mechanism transition from ‘passive wear’ to ‘active anti-wear’. The applied fields of the anti-wear mechanism are proposed as well.

Key words: Adhesive layer, High temperature tribology, Mullite-based composites, Wear mechanism, Zirconia oxide