Spray Parameter Effect on HVAF Sprayed (Fe, Cr)C-30FeNiCrSi Hardmetal Coatings

Abstract In this work, a design-of-experiments approach is used to map the main parameters of a high-velocity airfuel (HVAF) spraying process. Chromium carbide based material with a NiFeCrSi matrix was sprayed with varying gas flows and nozzle designs while monitoring their effect on particle temperature, velocity, and coating build-up. It was found that sufficient heating is critical to abrasive wear resistance and that particle temperatures are primarily controlled by fuel flow rates. Nozzle geometry, on the other hand, had the biggest effect on particle velocity, which was found to increase nearly 100 m/s by switching from a cylindrical to a convergent-divergent design.