Preparation and Characterization of MAO Film with High Dense Layer

Abstract

The influence of different negative current density on oxidation film thickness and dense layer thickness was studied. According to the results and experimental phenomenon，the negative current was adjusted steply, and the dense layer with high rates for 70% of micro-arc oxidation film was achieved. EDS and X-ray diffraction were used to analyse the composition and phase structure of the surface layer and the dense layer of oxide film .The friction coefficient and wear of the surface layer and the dense layer of oxide film were measured by wear machine measurement ,and were compared with hard anode oxidation film. The results show that the oxidation film thickness and the dense layer thickness increase with the rising of negative current density.The micro sparks can be avoided out, through adjusting negative current and a high dense layer of MAO film is got .The dense layer of MAO film contains only oxygen and aluminum elements, so it can not be effected by the electrolyte composition .The alpha Al2O3 level of the dense layer is higher than that of the surface layer, and the friction coefficient and abrasion loss of the dense layer is the lowest among the surface layer and hard anode oxidation film.