铝在混酸中的高压阳极氧化研究

Study on the high voltage anodization of aluminum in mixed acids

对铝在4种不同电解液体系中的高压阳极氧化的伏安特性进行了讨论.通过扫描电镜研究了不同电解液体系对铝高压氧化膜(HVAF)微观形貌的影响,并通过X-射线衍射实验研究了HVAF的结构.结果表明,铝在4种不同电解液体系中的高压阳极氧化过程均存在临界峰电流密度,即阳极氧化峰电流密度小于相应的临界峰电流密度时,铝表面不能形成完整均匀的HVAF;电镜实验证明,电解液的组成对HVAF的微观形貌影响较大,同时含钨酸钠、磷酸、草酸和成膜添加剂等组分的体系4,其HVAF表面存在规则有序的孔.

The volt-ampere characteristics of aluminum's high voltage anodization were studied in four different electrolyte systems. The influences of different electrolytes on the morphologies of aluminum's high voltage anodization film (HVAF) were studied with SEM (scan electron microscope). The structure of HVAF was studied by X-ray diffraction (XRD) method. Results show that a critical peak value of current densities exists in the aluminum's high voltage anodization process in four different electrolytes. And a complete and even HVAF is not formed when the current density is less than the peak value of current density. Electron microscope experiments prove obvious influences of the components in electrolyte on the film micromorphology. The pore is regular and ordered on the surface of HVAF gained from the fourth system containing sodium wolframate, phosphoric acid, oxalic acid and film-forming additive. The pore is round with size and density being 300 nm and 3×108～5×108 /cm2 respectively at low content of electrolyte, however the pore is regular hexagon with size being up to 500 nm at high content of electrolyte. It was found by XRD analysis that the film has a non-crystal structure and the intensity of diffraction peak becomes stronger with increasing oxidation time.