The fracture toughness and tribological performance of NiAl/Al₂O₃-40 Wt.% TiO₂ coating generated by air plasma spraying

Aluminum titanate ceramic coating materials have great a potential application in the mechanical and metallurgical fields. Al₂O₃-40 wt%TiO₂(AT40) is one of the most substantial ceramic materials, which is extensively used for thermal barrier coating due to its combination of excellent properties like high wear and corrosion resistance, high ductility, and density as well as a good deal of durability against fatigue. However, AT40 ceramic coating still faces some poor mechanical properties, such as low fracture toughness, combined with high hardness and brittleness, which limits to achieving widespread application. The doping of metals in AT40 ceramic composite coating positively affects the mechanical properties of AT40 ceramic coating. In this study, NiAl with different concentrations was doped in AT40 by air plasma spraying (APS) to produce NiAl/Al₂O₃-40 wt%TiO₂ composite coating, and its microstructure and mechanical properties were investigated by employing various characterization techniques. The results showed that a 20 wt% NiAl concentration in AT40 coating improved fracture toughness, strengthened bonding, and reduced 80–85% in crack propagation and porosity in the composite coating. Additionally, the 20 wt% NiAl coating displayed an excellent wear resistance, lower energy release rate, and lower micro hardness, compared to 0 wt% NiAl/AT40 coating.