Corrosion Resistance and High Temperature Oxidation Resistance of Zr-alloyed Layer Formed on 0Cr18Ni9Ti Stainless Steel Surface

Zr-alloyed layer was prepared on 0Cr18Ni9Ti austenitic stainless steel surface by double-glow plasma surface alloying technology,and then electrochemical corrosion tests were performed in 0.5 mol·L-1HCl solution,3.5 %NaCl solution and 0.5 mol·L-1 NaOH solution,respectively.Besides,high temperature oxidation experiments of the Zr-alloyed layer were carried out in static air at 1 000-1 150 ℃.The corrosion resistance and high temperature oxidation resistance of the Zr-alloyed layer were studied,and compared with those of the stainless steel substrate.The results show that,in the three types of solutions,the relative corrosion rate of the stainless steel substrate was respectively 24.43,2.44,1.90 times that of Zr-alloyed layer,the surface of the stainless steel substrate exhibited serious corrosion,but the Zr-alloyed layer only exhibited some localized corrosion pits,due to the formation of a dense ZrO2 passivation film on Zr-alloyed layer surface during corossion.The oxidation mass gain curves of the stainless steel substrate and the Zr-alloyed layer followed mainly the parabolic law.After corrosion at 1 150 ℃ for 20 h,the surface of the stainless steel exhibited severe oxidation,but the Zr-alloyed layer had a good surface morphology with less holes and the structure was very dense.