Effects Of Ultrasonic And Rare-earth On The Properties Of Anodic Aluminum Oxide Film

The paper introduces the technologies, types and applications of aluminum anodizing, the structure of anodic aluminum oxide film, as well as forming mechanism and current studying situation; particularly, advances about effects of rare-earth additives on strengthening aluminum and its alloys, and analyzes the shortcomings of these technologies. After analyzing and studying literatures at home and abroad, rare-earth and ultrasonic are determined to be used in the process of anodic oxidation as a measure for strengthening aluminum so that high quality oxide films can be obtained under not harsh terms.Pieces of industrial pure aluminum L3 and hard aluminum alloy LY12 with their size 2cm×2cm are anodized in H2SO4 electrolyte containing rare salts, at a result, it shows that the properties of their products are better than those of the one obtained in free rare salt H2SO4 electrolyte; And their optimum percents are 0.5% or so. In addition, composite rare earth salts are better than single salt for improving their properties.Ultrasonic with proper frequency which is not more than 20KHz can serves to improve the properties of anodic oxide film. Less than 20 KHz ultrasonic which acts in the anodizing process of H2SO4 electrolyte containing rare salt Ce(SO4)2.4H2O(its concentration is 0.5g/L) can significantly improve the properties of anodic aluminum oxide film; but over high frequency may degrade the quality. There is not found any rare-earth elements in the oxide films with the use of XPS, which only acts as a catalyst.