Microwave plasma CVD of diamond films on high concentration alloys: Microstructure, hardness and wear properties

Abstract

Polycrystal diamond films were synthesized on high concentration alloys (HCAs) by microwave plasma chemical vapour deposition. It was found that the continuous diamond films formed in a short period, e.g., 10 min. The carbides including the stable MC [0 1 1] (M = Mo, Nb, Ta, Ti and Zr) and metastable carbides (e.g., Mo2C, Ti2C and Mo3C2) were identified by X-ray diffraction and transmission electron microscopy. The diamond/carbide interface had an orientation relationship as [0 1 1]Diamond//[0 1 0]Mo2C. The hardness of MoHfNbTaTiZr HCA at the CH4 concentration of 9% for 20 min was as high as 1238.2 HV0.3. The friction coefficient was 0.56–0.73 for the specimens with continuous diamond films. No spallation of films after friction indicated good wear resistance and adhesion.