Preparation of alumina coating on stainless steel surface by cathodic plasma liquid deposition

Al₂O₃ coating with a thickness of 40 μm was produced on a stainless steel substrate by cathodic plasma liquid deposition (CPLD). The influence of current density on the phase compositions and microstructures of the coating was investigated, and the growth mechanism of the coating was analyzed. The coating was composed of α-Al₂O₃ and γ-Al₂O₃. The content of α-AI₂O₃ increased with increasing current density, which amounts to 86% for current density 8 A/dm². The coating surface was coarse and porous, and more big grains and fewer pores present on the surface with increasing current density. Fe in the substrate do not come into coatings, and Al and O decrease from the substrate to the coating surface.