The influence of aluminum treatment and anodizing conditions on the galvanoluminescence properties of porous oxide films formed in sulfuric acid solution

In this article, we have presented our recent investigation of luminescence originating from thin oxide film obtained by aluminum anodization in sulfuric acid solution. For the first time we have measured this weak galvanoluminescence (GL) and found strong influence of sample's surface pretreatment as well as anodization conditions (current density, temperature of electrolyte and electrolyte concentration) on luminescence intensity. GL intensity is the highest for degreased samples, lower for chemically cleaned and almost disappears for electropolished samples. Results obtained in sulfuric acid confirmed the previous measurements in phosphoric and chromic acid that GL intensity is higher for higher current density, lower electrolyte temperature and lower electrolyte concentration.