Abstract: The passivation process of adding 500 ppb copper ion to 30 wt.% nitric acid passivation solution was studied to inhabiting bacterial biofilms on stainless steel of washing machine inner cylinder. The experimental results show that the passivation treatment changed the properties of the passive film on the surface of 430 stainless steel, and significantly improved the corrosion resistance, antibacterial and antifouling properties of the material. The pitting potential of the material was increased more than 200 mV and the antibacterial rate achieved over 99.99%, and does not affect the matrix structure. It has great prospects for application in the preparation process of stainless steel in the inner cylinder of washing machines.

Key words: Washing machine, Stainless steel, Antibacterial, Passivation