The ability of metallic materials to resist dielectric erosion in corrosive media is called corrosion resistance of metals. The high corrosion resistance of the genus of pure gold usually has one of the following three conditions: ① the thermodynamic stability of high metals. It is usually judged by its standard electrode potential, whose value is higher than that of the positive stability, and the negative is lower stability. The precious metals, such as PT, AU, AG, CU, etc. are of good corrosion resistance. ② Easy passivation Metal. Many metals can form a dense oxide film with protective effect in oxidation medium, which is called passivation. The most likely passivation in metals is Ti, ZR, TA, NB, CR and al. ③ surface can produce insoluble and protective properties of good corrosion products film of metals. This situation occurs only in a specific corrosive medium, for example, Pb and Al in H2SO4 solution, fe in H3PO4 solution, MO in hydrochloric acid and Zn in the atmospheric medium.