The research on metal passive film is progressing from macro-study to micro-study stage including analysis on structure and composition. Generally

the spontaneous formed thin and stable passive film on stainless steel mainly consists of metal oxides. The thickness of passive film is no more than 10 nm

determined by the factors including chemical composition of stainless steels

pH value of solution

electrical potential and temperature. The thickness

composition and structure of passive film of stainless steels

the passive film formation and growth mechanism

the performance of semi-conductivity and the corrosion resistance of passive film are reviewed

and the effect of nanostructure on performance of passive film of stainless steels is discussed. At present

the research focal point is to develop new stainless steels with high strength

well wearing resistance and excellent corrosion resistance

while application of nanotechnology is one of available ways.