Effect of HVOF Air Cap Nozzle Grooves on Cr₃C₂+ 20NiCr Coating Characteristics

Abstract

The air cap nozzle grooves were modifying in the HVOF system by adding 2 and 4 vertical grooves to analyze the effect on the quality of the Cr3C2+20NiCr ceramic coating, then compared with the original (smooth) nozzle. With constant parameters of the HVOF process, such as spraying distance, time, and pressure of the gas fuel, this experiment will determine the quality of the coating, namely the thickness, hardness, and porosity observed through the ceramic coating cross-section. The results of porosity analysis using SEM and image analysis show that a nozzle with 4-grooves has a porosity of 2.42%. In contrast, the nozzle with 2-grooves has a porosity of 2.85%, and the original (smooth) nozzle has a porosity of 4.42%. The low porosity of the nozzle with 4-grooves increases the bond strength due to the lowest degree of particle porosity.