Abstract
This study investigates the feasibility of suspension plasma spraying with a twin-cathode gun that incorporates three plasma torches. Suspensions are fed axially through the hollowed anode of the main torch, producing a plasma that merges with radially directed plasmas from two opposing sub-torches. All of the feedstock powder is fully entrapped and melted in the combined plasmas prior to impact with the substrate surface. This leads to higher deposition efficiencies and allows high feed rates to be used during spraying. Several ceramic coatings with different melting points were fabricated using the newly developed system. Spray trials were also conducted to evaluate the extent to which microstructure can be controlled by varying suspension concentration.
