High-temperature oxidation behavior and tribological performance of nickel-based alloy coatings reinforced with ZrB2 ceramic

NiCr-ZrB 2 , NiCrBSi-ZrB 2 , and NiCrAlY-ZrB 2 powders were prepared by mechanical alloying and subsequently deposited as coatings using the HVOF. The oxidation resistance and tribological properties of the coatings were evaluated at 700 °C. Results show that all three composite coatings exhibit porosity below 1%, with ZrB 2 particles uniformly distributed in the matrix. The NiCrBSi-ZrB 2 coating contain additional hard precipitates (Ni 3 B and Cr 2 B), resulting in a microhardness of 689.63 HV 0.5 , which significantly higher than NiCr-ZrB 2 (479.86 HV 0.5 ) and NiCrAlY-ZrB 2 (642.95 HV 0.5 ) coatings. After oxidation, all coatings develop protective oxide scales composed of NiCr 2 O 4 , ZrO 2 , and NiO. Notably, the NiCrBSi-ZrB 2 coating additionally form self-healing SiO 2 , contributing to its low oxidation weight gain of 0.20 mg/cm 2 . During wear testing, the formation of a protective oxide film, comprising a ZrO 2 skeletal structure, self-healing SiO 2 , along with NiCr 2 O 4 , Cr 2 O 3 , and NiO, effectively suppress crack propagation and spalling pit formation. Consequently, the NiCrBSi-ZrB 2 coating demonstrates superior wear resistance with an ultralow wear rate of 1.97×10 -13 m 3 /(N·m).