Plasma spray deposition of fly ash onto mild steel substrates using a fractional factorial design approach

Abstract In this study, fly ash was used as a feedstock material for atmospheric plasma spray deposition onto commercial marine-grade mild steel substrates. The experiments were conducted according to a fractional factorial design with four process parameter variables: the primary and carrier gas pressures, the powder feed rate and the plasma power. The results obtained indicate that the primary gas pressure was the most significant factor affecting the thickness and surface roughness of the deposited coatings, whereas the microhardness was affected by the primary gas pressure, the plasma power and the interaction between the primary gas pressure and the powder feed rate.