Improvement of Wear Resistance by Thermal Spraying on Surface Layers Prepared by Plasma Transferred Arc Welding on Gray Cast Iron Components

This study evaluates the erosion-corrosion performance of thermal spray hardcoats on bronze-coated gray cast iron. In the experiments, gray cast iron plates are coated with a bronze powder by PTA welding and the coatings are characterized based on microstructure and corrosion and wear testing. The bronze coatings provide good corrosion protection, but are shown to be susceptible to cavitation and erosion wear. To compensate, thermal spray hardcoats, including atmospheric plasma sprayed Al₂O₃ and Cr₂O₃ and HVOF sprayed WC-Co, were applied over bronze-coated cast iron and corrosion and wear tests were performed. It is shown that the thermal spray hardcoats greatly improve wear resistance, but despite their interconnected porosities, do not affect the corrosion performance of the underlying bronze.