Study of temperature effect on carbide layer formation behaviour of dual elements thermal reactive deposition on SUJ2 steel substrate

In this research, the formation of carbide layer coating on SUJ2 steel by pack Thermal Reactive Deposition method was studied. Mixture of 35/65 weight percent of ferrochromium/ferrovanadium (FeCr/FeV) powder was applied as coating elements. The process was carried out at temperatures of 900, 950, and 1000 °C for 6 hours for each temperature. The effects of temperature on layer thickness, microstructures, homogeneity, hardness, and wear resistance were analyzed. The result showed that the higher the temperature, the thicker the layer formed on substrate surface. The higher percentage of vanadium in the coating layer compared to chromium found by EDS Linescan results indicate that vanadium has higher affinity to carbon than chromium. This result also means the possibility of vanadium carbide formation will be higher than chromium carbides, due to the lower Gibbs energy for vanadium carbide formation. XRD results showed that the layer formed in this process consists of vanadium carbide (V8C7 and V6C5), chromium carbide (Cr23C6 and Cr7C3), and complex carbides. The average micro hardness and wear rate of all coatings with three different temperature variations were 2100 HV, and 3 × 10^-4 mm³/m respectively. This hardness was close to FeV hardness as single carbide former at approximately 2400 HV.