We investigated the effect of Cr thin film deposition on the thermal stability and corrosion resistance of hot-dip aluminized steel. A high-quality Cr thin film was deposited on the surface of the Al-9 wt. % Si-coated steel sheets by physical vapor deposition. When the Al-Si coated steel sheets were exposed to a high temperature of 500℃, Fe from the steel substrate diffused into the Al-Si coating layer resulting in discoloration. However, the highly heat-resistant Cr thin film deposited on the Al-Si coating prevented diffusion and surface exposure of Fe, improving the heat and corrosion resistances of the Al-Si alloy coated steel sheet.

The effect of plasma-radical change on the surface properties of Zn-Mg-Al ternary-alloy-coated steel sheets during atmospheric-pressure (AP) plasma treatment using different process gases: O ₂, N ₂, and compressed air was investigated. The plasma-induced radicals promoted the formation of chemical particles on the surface of the Zn-Mg-Al coating, thereby increasing the surface roughness. The surface energy was calculated using the Owen-Wendtgeometric equation. Contact angle measurements indicated that the surface free energy of the alloy sheets increased upon AP plasma treatment. The surface properties of the Zn-Mg-Al coating changed more significantly in the order air > O ₂ > N ₂ gas, indicating that the plasma radicals facilitated the carbonization and hydroxylation of the Mg and Al components during the AP plasma treatment.