Enhancing the wear and high-temperature oxidation behavior of NiCrBSi coatings by collaboratively adding WC and Cr3C2

Abstract

A composite coating was deposited by collaborative modification with tungsten carbide (WC) and Cr3C2 ceramic particles to improve the wear resistance of NiCrBSi coating over a wide temperature range. The original NiCrBSi coating and the composite coatings with WC and Cr3C2 collaboratively (NiCrBSi +20 wt% WC–Cr3C2–Ni) and exclusively (NiCrBSi +20 wt% WC and NiCrBSi +20 wt% Cr3C2–NiCr) added were designed and deposited by plasma spraying. The microhardness of the composite coatings added with the ceramic phase was higher than that of the NiCrBSi coating. The composite coating with the addition of WC showed the maximum microhardness (896.8 HV). The wear mechanism of the four coatings at room temperature was dominated by fatigue spalling, whereas oxidative and abrasive wear prevailed at 700 °C. The composite coating (NiCrBSi +20 wt% WC–Cr3C2–Ni) showed excellent abrasion resistance at room temperature and 700 °C. The wear volume of the composite coating (NiCrBSi +20 wt% WC–Cr3C2–Ni) decreased by 83.5 % and 46.9 % at room temperature and 700 °C, respectively, compared with the wear volume of the NiCrBSi coating. In general, high WC hardness was favorable for improving the microhardness of the coating. The preferential oxidation of Cr3C2 instead of WC promoted the formation of a dense oxide film on the surface of the coating and reduced oxidation within the coating. This study revealed the mechanism of the collaborative enhancement of NiCrBSi coatings by WC and Cr3C2 and the improved wear resistance of the NiCrBSi coatings at room and high temperatures.