Research Progress and Application of Rare - Earth Conversion Film in Metal Corrosion Protection

The rare earth conversion film has attracted more and more attention in recent years because of its good corrosion resistance and non - toxicity. The concept and film forming mechanism of rare earth conversion film were briefly introduced, and the application of rare earth in corrosion prevention for ferrous metals as well as the nonferrous metals of aluminum, magnesium, zinc and their alloys was summarized. This study found that the corrosion resistance of composite rare earth conversion film was better than that of the single rare earth conversion film. Moreover, it also explained the reason why cerium conversion film had better corrosion resistance than other rare earth conversion films. Finally, it pointed out that the composite rare earth conversion film, rare earth composite alloy coating and densification of rare earth conversion film would be the development direction.