Anodic Oxidation and Coloring of Aluminum Powders

摘要

To improve the anticorrosive characteristics of organic coatings (e.g., paints, enamels, etc.), some kinds of pigments are used; among them of special importance are aluminum powder pigments, mainly for the automotive industry. They significantly reduce organic solvent emission to the atmosphere during paint application. A problem that is met with aluminum powder pigments is corrosion in alkaline media (pH > 8), which favors hydrogen evolution according to the reaction: 2 Al + 6H_2O → 2 Al(OH)_3 + 3H_2 (1) This implicitly leads to color paint degradation.