Tribological properties of laser cladding NiAl intermetallic compound coatings at elevated temperatures

Tribological properties, phase compositions and wear mechanisms of laser cladding NiAl coating were investigated from room temperature to 1000 degrees C under air atmosphere environment. The results showed that a glaze layer composed of NiO, Ni2O3, Al2O3 and NiAl2O4 phases as well as Ni3Al phase were formed on worn surface under high temperature, which act as a solid lubricant and anti-wear material improving the tribological properties of NiAl coating at elevated temperatures. The wear mechanism is dominated by abrasive wear below 500 degrees C, and transforms to plastic deformation and adhesive wear at 500 degrees C up to 700 degrees C and oxidation wear at 900 degrees C and above, owing to formation of new oxide phase during tribochemical reaction.