THERMODYNAMIC PREDICTION OF DEPOSITION PARAMETERS FOR DIAMOND SYNTHESIS IN ATMOSPHERIC OXYACETYLENE FLAMES

The suitable ranges of substrate temperature and gas flow ratio for di amond synthesis in atmospheric oxyacetylene flames are theoretically p redicted by a non-equilibrium thermodynamic coupling model. The suitab le range of substrate temperature is widest for flow ratio R close to unity, and will be narrowed rapidly when flow ratio deviates from unit y. When the substrate temperature is between 1000 and 1250 K, the corr esponding R range is about between 0.8 and 1.1. Diamond synthesis is a llowed thermodynamically for flow ratio beyond 1.1 though the kinetic rate might be very low.