Wear engineering oxides antiwear oxides

The tribological behavior of self-mated ceramic composites, like SiC-TiC, S i3N4-TiN and (Ti, Mo) (C, N)+Ni, were characterized under dry-sliding frict ion. The coefficient of friction still remains unchanged on a level known f rom SiC and Si3N4, ceramics. The addition of titanium compounds to SiC and Si3N4, ceramics reduced the wear rate compared to titanium-free ceramics. I ncreasing sliding speed and temperature enhances this trend. The (Ti, Mo) ( C, N) materials exhibited a wear behavior nearly independent from sliding s peed and temperature with wear rates lower than 10(-7) mm(3)/Nm up to 800 d egrees C. The present study utilized small-spot X-ray diffraction, laser ra man spectroscopy (LRS) and transmission electron microscopy (TEM) TiO2 and TinO2n-1-type crystalline Magneli-phases with a crystallographic shear stru cture as well as some double oxides like NiTiO3, Mo0.975Ti0.025O2 and beta- NiMoO4 were detected on different ceramic substrates formed by tribo-oxidat ion during rests at 400 degrees C and 800 degrees C. The conditions during tribological operation are sufficient to generate crystalline Magneli-phase s by tribo-oxidation, like gamma -Ti3O5, Ti5O9 and Ti9O17.