Deposition and properties of plasma sprayed NiCrCoMo–TiC composite coatings

Abstract

In this study, NiCrCoMo–TiC composite coatings were plasma sprayed using NiCrCoMo alloy powders and Ti–C powders. The microstructure, micro-hardness, and wear behaviours were investigated. NiCrCoMo coating consisted of Ni–Cr–Co–Mo phase. NiCrCoMo–TiC coatings consisted of Ni–Cr–Co–Mo, TiC, and TiO2 phases. The average porosity of NiCrCoMo coating was about 5.5 ± 0.6% and it increased to 10.1 ± 0.9% after adding 25 wt% Ti–C powders. All the coatings had a thickness of ≥200 μm with a layered structure. The micro-hardness of NiCrCoMo–TiC coatings increased with the addition of Ti–C powders, and it increased by 39% to 854HV0.2 as the added Ti–C powders was 25 wt%. The friction coefficient of NiCrCoMo coating was 0.43, and that of NiCrCoMo–TiC coatings was 0.60–0.64. The wear volume of NiCrCoMo–15TiC coating was 0.3099 mm3, which was just 28% of that of NiCrCoMo coating. The wear mechanism of NiCrCoMo–TiC coatings was adhesive wear, fatigue wear and abrasive wear.