Aluminum etchants are an integral part of anodizing. Successful anodizers understand that there are a number of variables to consider when seeking to optimize the etching process.
Caustic content, time, temperature and dissolved aluminum content are just some of the macro considerations. Surface morphology, level of gloss and even the color of the anodized film is impacted by the etch technology and the manner in which it is operated.
This paper summarizes the findings of a study on the effect of varying levels of aluminum in a low caustic solution used after an acid etch process.