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Combustion Synthesis of Diamond Films�

Nandyal, Srihari
Diamond films were synthesized using an oxy-acetylene flame on a polished molybdenum substrate. The effect of different. parameters such as gas flow rates, ratio of oxygen to acetylene, separation of the inner cone from the substrate, and acetylene cylinder pressure were studied. The morphological characteristics of the diamond films were then examined under a scanning electron microscope and their quality assessed using uRaman spectroscopy. A growth mechanism is proposed which explains the evolution of different crystalline forms of diamond from the cauliflower-like structures. The use of this hypothesis could enable the synthesis of diamond crystallites with a preferred orientation. The effect of the acetylene cylinder pressure on the transparency of the diamond f'llms grown has been addressed and a plausible cause for the improvement in f'llm quality is given. A method for growing uniform films has been proposed based on the shape of the stagnation zone in the flame.