Effects of vacuum plasma spray processing parameters on splat morphology

Several statistical tools (i.e., Gaussian and Weibull distribution analyses, the t-test, and analysis of the variance) were used to examine relationships between vacuum plasma spray processing parameters and the morphology of flattened particles (splats) on a smooth, polished substrate. Astroloy, a nickel-base powder, was vacuum plasma sprayed onto polished copper substrates under various processing conditions. Different flattened particle shape factors, including equivalent diameter, elongation factor, and degree of splashing, were determined using image analysis. The spray parameters (i.e., current intensity, chamber pressure, argon mass flow rate, etc.) strongly influenced splat formation and morphology and thus deposit microstructure and properties.