Penetration treatment of plasma spray SUS316L stainless steel coatings by molten multi-component oxides

• Multi-component oxides could seal the open pores in stainless coating in 20 min.
• Multi-component oxides could infiltrate into the inter micro-pores in 45 min.
• The penetration treatment resulted to be more effective with increasing temperature.

A study of the effects of penetration treatments on plasma sprayed SUS316L stainless steel coatings was performed. The stainless steel coatings were sealed using multi-component oxides introduced at the conditions of 1273 K for 20 min, 1273 K for 45 min and 1373 K for 45 min. The effectiveness of the penetration was determined using an electron probe microanalyzer (EPMA). The results indicated that the molten multi-component oxides could seal the open pores near the stainless steel coating surface quickly and effortlessly due to the good wettability. The molten multi-component oxides could pass through the oxide path connected to the inter micro-pores smoothly and infiltrated into the stainless steel coating when the period of impregnation was prolonged to 45 min. The penetration became more effective with increasing temperature because of the reactions between the molten multi-component oxides and the original oxides that occurred in the stainless steel coating around the inter pores. The results of a salt spray test indicated that the penetration treatment could significantly improve the corrosion resistance of the stainless steel coating.