RF Plasma Deposition of Refractory MetalsCase Study for Tungsten

摘要

The paper presents an integrated study of the effects of RFplasma 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 bothexperimental and numerical simulation methods, as functionsof spray particle diameters. In-flight spheroidisation behaviorwas also observed by means of a particle capturing techniquewhile splat formation was studied on polished stainless steelsubstrates. Optimized process parameters were then estimatedand used to produce deposits on stationary substrates. Depositproperties, such as splat shape and crystal grain morphologies,apparent densities and deposition efficiencies were observedand processing parameters further optimized. The resultsobtained indicate that the advantages of the RF inductivelycoupled plasma spray technique, such as the longer particleresidence time in the plasma and "cleanliness" of the processcan be efficiently utilized to deposit dense tungsten metal partsor coatings.