Dependence of the diamond coating adhesion on the microstructure of SiC-based substrates

Diamond thin films were deposited on the SiC-30TiC-10Cr(3)C(2) substrates b y using the microwave plasma CVD method and the effect of microstructural m orphology of substrate was examined on the diamond-substrate adhesion stren gth. Two types of substrate were prepared by hot-pressing, one with small a nd equiaxed beta-SiC grains and the other with large and elongated alpha-Si C grains. The SiC-30TiC-10Cr(3)C(2) substrate surfaces were chemically etch ed to remove (Ti,Cr)C matrix phase by Murakami solution. Better diamond-sub strate bonding was obtained on the substrate composed of large, elongated g rains. Vickers indentation results indicated that mechanical interlocking b etween elongated and protruded grains on the etched surface and diamond thi n him resulted in an increase in adhesion strength. (C) 1999 Elsevier Scien ce S.A. All rights reserved.