Diamond and Related Materials: International Journal on the Science and Technology of Diamond and Related Materials vol:9 issue:3-6 pages:341-345
In this paper we present our first preliminary results on chemical vapour deposition (CVD) of diamond onto nitrided chromium using an oxyacetylene flame. Polycrystalline diamond films were obtained after deposition at very low substrate temperatures (<400 degrees C). At these low temperatures there was extremely weak bonding, or no bonding at all, between the deposited layer and the substrate. To obtain stronger bonding, four growth experiments were carried out at initially higher substrate temperatures (700-1000 degrees C). Whilst growth continued, the substrate temperatures were lowered step by step to 250 degrees C. It was observed that on lowering the substrate temperature by more than about 500 degrees C from the initial temperature, delamination occurred, suggesting that the thermal stresses exceeded the bonding strength. Subsequently, adherent diamond coatings were grown on the freshly exposed substrate surface whilst further lowering the substrate temperature. These diamond coatings were characterized using scanning electron microscopy and the adhesion of the diamond coatings to the substrates was assessed by means of the scotch tape test. (C) 2000 Elsevier Science S.A. All rights reserved.