Plasma-Sprayed Nanodiamond-Reinforced NiCrBSi Composite Coating for Improved Wear and Corrosion Resistance

Abstract

NiCrBSi-based composites are immensely in demand to replace hard chrome coating for wear, corrosion-resistant applications and necessary to scale up the production. In the present work, we fabricated 1wt.% and 2wt.% nanodiamond (ND)-reinforced NiCrBSi composite coatings and evaluated the microstructural, mechanical, tribological and corrosion behavior comparing it with bare NiCrBSi coating. Our findings showed that the ND-reinforced plasma-sprayed NiCrBSi exhibited relative density up to 97.7% and offered strong mechanical properties, viz. hardness: ~ 1076.8 HV and elastic modulus: ~ 93.2 GPa. Also, the presence of outer graphitic shells in the detonated ND ignited tribological performance, restricting its wear rate at 0.21 ± 0.043 × 10⁻⁵ mm³/N.m. Further, the corrosion study proved that the incorporation of ND acted as a barrier to mitigate the corrosive electrolyte and enhanced the corrosion resistance rate by 93.70%. The involved synergetic mechanisms have been discussed in terms of lamellar structure and associated stacked splat, splat adhesion, etc. Hence, the ND-reinforced plasma-sprayed NiCrBSi coatings can be recommended as a protective coating in automotive and aerospace sectors.