AN EXPERIMENT IN LARGE AREA DIAMOND COATING USING A COMBUSTION FLAME TORCH IN ITS TRAVERSING MODE

Synthesis of diamond films by conventional chemical vapour deposition methods using a vacuum chamber is difficult when coating a large area substrate because of the limited space in the chamber. This paper deals with an experiment in which a large area substrate is diamond coated using a combustion method which does not have this problem. A tungsten substrate (50 mm x 50 mm x 5 mm) was used, over which an oxyacetylene combustion flame was passed at a speed of 2 mm min-1 to obtain a diamond coating. By establishing an optimum combination of coating parameters, including gas flow rate and substrate cooling rate, the substrate could be completely coated with a good diamond film over an area of approximately 40 mm x 40 mm.