TSA is a type of anodizing that results in a thin oxide layer with optimal adhesion properties and a good corrosion resistance. Like all types of anodizing, aluminum is converted into aluminum oxide, as a result of which optimal adhesion is guaranteed. TSA is applied if strict requirements are imposed on corrosion resistance and sulphuric anodizing is not an option due to the negative effects on the fatigue strength. The TSA-process is mainly applied to aerospace components. A large number of fine pores occur in the oxide layer during the treatment which are normally not sealed after anodizing, because most of the time TSA is used as a pre-treatment before paint application.