Effect of ZrB2 Addition on Sintering Temperature and Densification of Vacuum-Fused NiCr/WC Cermet Coating

Abstract NiCr/WC cermet coatings were fabricated by vacuum fusion sintering on the surface of nickel-base alloy at 1220 °C. The sintering temperature, densification mechanism and oxidation resistances of the cermet coating with ZrB2 additive were investigated using thermogravimetric and differential thermal analysis method, theoretical calculation of phase diagram with the FactSage software, X-ray diffraction, and scanning electron microscopy. The sintering temperature of NiCr/WC cermet coating with ZrB2 additive decreased 123 °C and obtained the dense cermet coatings. The densification mechanism of NiCr/WC cermet coating added ZrB2 is mainly attributed to the reaction occurred between Ni and ZrB2 and the ample liquid phases formed at 1220 °C. The surface of the WC particles is coated by CrxCy and surrounded by NiCr alloy result in the better oxidation resistance of the cermet coating added with ZrB2.