Investigating the Effect of Poly-tetra-fluoro-ethylene on the Cavitation-Erosion and Corrosion Resistance of HVOF Sprayed TiC Coatings on Stainless Steel

Abstract

This research investigates; ways to improve material resistance to cavitation erosion and corrosion by using surfaces coated with PTFE and TiC applied through HVOF spraying. Optimal conditions were identified by the application of response surface methodology, leading to a significant decrease in mass loss. In material-specific reactions, HVOF-sprayed TiC showed increased resistance to cavitation because of its inherent micro-hardness (1293 HV). The reactivity of samples sprayed with PTFE varied, suggesting a complicated interplay between the properties of PTFE and jet velocities. SEM images verified the effectiveness of the PTFE and TiC coatings sprayed by HVOF as shields against corrosive elements. Even after seven cycles in a cyclic corrosion test, PTFE demonstrated outstanding corrosion resistance and impermeability, while the TiC coating created a dense, stable oxide layer. Furthermore, the combination of laser texturing and TiC and PTFE coatings sprayed with HVOF caused surfaces to exhibit superhydrophobic behavior (water contact angle: WCA > 155°). Extensive mechanical analyses provided information on surface roughness, bond strength, porosity, and microhardness, which helped to explain TiC's resilient resistance to indentation and strong adhesion (71.2 MPa) to the substrate. These findings offer practical methods and coatings to increase material resistance in conditions where cavitation and corrosive environments are common.