Microstructure and Wear Behaviors of Plasma Spray Welded High Al Bronze Coatings on Different Substrates

High Al bronze coatings was fabricated on different substrates by plasma spray welding. A pin-on-disk wear machine was employed to investigate the element diffusion effects on coating microstructures and its tribological properties. Results indicate that the wear and friction properties of coatings on different substrates were different under dry sliding. Abrasive and adhesive wear on the high Al bronze coating on 45 carbon steel substrate had high friction coefficient beacuse of strong adhesion between k phases and Fe on the counterpart material. Coating on ZQAl_9-4 substrate was composed of a lot of (α+ γ₂) net-like eutectic phases, which was brittle and decreased the coatings impact toughness. Fatigue and abrasive wear and low wear resistance were observed. However, for the coating on T3 copper substrate, k phases were uniformly distributed in the β' phase and thus coatings were hardened by the refined coatings microstructure due to high thermal conductivity of T3 copper, which produced low friction coefficient and wear rate.