Wear and Corrosion Properties of Stellite-6 Coating Fabricated by HVOF on Nickel–Aluminium Bronze Substrate

Ni–Al bronze (NAB) was coated with Stellite-6 through gas-fueled high-velocity oxyfuel spraying. Scanning electron microscopy observations revealed the accumulation of Tungsten-rich particles at the substrate-coating interface. These areas played an important role in the enhancement of the mechanical properties of the coating. The coating hardness increased 5 times with respect to the substrate one. The tribological analysis of the coating was done via pin on disk method. Results showed that abrasive wear is the dominant mechanism for the substrate; on the contrary, delamination is the dominant wear mechanism in the coating. The corrosion performance of bare and coated alloy was investigated by potentiodynamic polarization and electrochemical impedance spectroscopy. The corrosion potential of coated sample increases in comparison with bare alloy, corrosion current density decreases from 3.91 to 1.82 µA/cm2 and the capacitive resistance is much larger.