Abstract
The paper presents an integrated study of the effects of RF plasma spray process parameters on the particle melting, particle spheroidisation and acceleration in the plasma, particle-substrate interactions and final deposit properties. Particle temperatures and velocities have been studied, by both experimental and numerical simulation methods, as functions of spray particle diameters. In-flight spheroidisation behavior was also observed by means of a particle capturing technique while splat formation was studied on polished stainless steel substrates. Optimized process parameters were then estimated and used to produce deposits on stationary substrates. Deposit properties, such as splat shape and crystal grain morphologies, apparent densities and deposition efficiencies were observed and processing parameters further optimized. The results obtained indicate that the advantages of the RF inductively coupled plasma spray technique, such as the longer particle residence time in the plasma and “cleanliness” of the process can be efficiently utilized to deposit dense tungsten metal parts or coatings.
