Exploring Slurry Abrasion Resistance of HVOF-Sprayed VC and CoNi Coatings: A Response Surface Methodology Approach

Abstract

Slurry abrasion (SA) evaluation is critical for assessing the wear resistance of coated surfaces under harsh operating conditions. This study investigates the performance of HVOF-sprayed vanadium carbide (VC) and VC-50CoNi coatings applied to SS316 substrates, focusing on their behavior under varying loads, slurry concentrations, and abrasive particle sizes. The mass loss during SA testing was normalized with respect to the exposed surface area (mg/cm²), providing a clear comparative analysis. Under a load of 137.2 N, particle size of 100 µm, and slurry concentration of 25,000 ppm, the VC coating exhibited the lowest mass loss of 0.158 mg/cm², while the VC-50CoNi coating demonstrated a moderate mass loss of 0.302 mg/cm². These results were compared to the uncoated SS316 substrate, which suffered the highest mass loss of 0.773 mg/cm². The novelty of this study lies in identifying the underlying mechanisms contributing to the wear behavior of these coatings. SEM analysis revealed that the superior wear resistance of VC coatings is attributed to their high hardness (1365 HV), which minimizes abrasive material removal through spalling and delamination. In contrast, the addition of Co-Ni in VC-50CoNi coatings enhances toughness, reducing crack propagation but slightly increasing mass loss due to fatigue cracking and surface roughening. The response surface methodology effectively optimized the process parameters, with statistical tests confirming the accuracy of the predictive model. These findings provide new insights into the design of wear-resistant coatings for industrial applications, emphasizing the balance between hardness and toughness achieved in composite coatings.