O. Kovarik, University of Sherbrooke, Sherbrooke, QC, Canada; S. Xue, Tekna Plasma Systems Inc, Sherbrokke, QC, Canada; X. Fan, M. Boulos, Tekna Plasma Systems Inc., Sherbrooke, QC, Canada
The paper presents an integrated study of the effects of RF plasma spray process parameters on particle melting, particle spherodisation and acceleration in the plasma, particle-substrate interactions and deposit properties. Particle temperatures and velocities have been studied, both experimentally and by numerical simulation, as functions of particle diameters. The in-flight spheroidisation behavior was also observed by a particle trapping technique and splat formation has been 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 and crystal grain morphologies, apparent densities and deposition efficiencies were observed and the process parameters further optimized. The results obtained indicate that the advantages of RF inductively coupled plasma spray technique, such as longer particle in plasma residence time and “cleanliness” of the process can be efficiently utilized to deposit dense tungsten metal parts.
Summary: The study of the effects of RF induction plasma spray process parameters on plasma characteristics, particle in flight behavior and final deposit properties was conducted. The results obtained enabled the optimization of the spray process in order to produce a high density tungsten deposit with high deposition efficiency.