THE INFLUENCE OF THE ANODIZATION TEMPERATURE AND VOLTAGE ON THE POROSITY OF THE ANODIZATION LAYER ON ALUMINUM

The pore-filling method is a known process for measuring the porosity of porous anodic oxide layers on aluminium. This method has been used to study the relationship between the anodizing conditions and the por osity of the porous anodic film. In a series of experiments, the influ ence of the anodization voltage and temperature on the porosity of an anodization layer formed in 15 wt.% sulphuric acid was investigated. F rom these results a mathematical equation was deduced that gives the p orosity as a function of the anodization voltage and temperature. In t he second part of the study the height of the voltage jump, on which t he thickness of the barrier layer at the start of the re-anodization p rocess depends, was investigated as a function of the anodization volt age. A linear relationship was found between the voltage jump and the anodization voltage.