Tribological properties of WC and CeO2 particles reinforced in-situ synthesized NiAl matrix composite coatings at elevated temperature.

WC and CeO2 particles reinforced in-situ synthesized NiAl matrix (WC/CeO2/NiAl) composite coatings were prepared on aluminum alloys by laser surface alloying. The microstructure, microhardness and fracture toughness as well as the tribological properties at 25°C and 400°C of the composite coatings were investigated. The results show that the WC/CeO2/NiAl composite coating contains the phases of NiAl, WC, W2C, γ-(Fe,Ni), CrB, Cr23C6, Al3Ni2 and CeNi5. Due to the synergistic strengthening effects of WC and CeO2 particles, the average grain size of the composite coating is reduced, and the microhardness and fracture toughness are increased. The friction coefficient and wear loss of the composite coatings rise in ascending order with the temperature, which are smaller than those of the WC/NiAl composite coatings, the NiAl coatings and the substrates. As the temperature increases from 25°C to 400°C, the wear mechanisms of the composite coatings change from micro-cutting wear into multi-plastic deformation wear and slight oxidative wear. [ABSTRACT FROM AUTHOR]