9309669 Zhang This research concerns development of diamond growth techniques in which the oxyacetylene combustion synthesis method is employed. The project involves design and construction of a diamond growth apparatus consisting of an oxyacetylene welding torch, fitted with a brazing or cutting nozzle, two mass flow controllers and a mass flow programmer, etc., and growth of diamond films on a variety of cutting tool materials. The ultimate goal is to apply the research findings to an industrial situation, namely to produce viable, inexpensive techniques of diamond coating on various cutting tools for manufacturing applications. Currently, the mechanisms for nucleation of the diamond phase and for adherent bonding of diamond film to the substrate are not will understood, making the application of this technology very limited. The research will investigate the nucleation mechanisms of diamond phase involved in the diamond growth processes. The investigation will include pretreatment of substrate surfaces in various conditions, detection of dangling bond densities on the pre-treated substrate using the electron paramagnetic resonance (EPR) technique, and analysis of the precursor gas within and beyond stagnation zone of the acetylene flame using the residual gas analysis technique. Nucleation mechanisms of diamond phase will be researched by incorporating studies of chemical species of precursor gas and dangling bond densities of the substrate. Parametric studies will be towards enhancing nucleation density of diamond phase and improving quality of diamond films. The researcher will seek to develop a fundamental understanding of these mechanisms which will facilitate the application of oxyacetylene combustion synthesis of diamond films to industrial applications.
