| 摘要 |
<p>COATING SYSTEM A novel process is disclosed for the production of colored coatings on articles of aluminum or aluminum alloys. The process involves first forming a hard, dense anodic coating of between about .2 to about 1.1 mils on the aluminum or aluminum base alloys by anodizing the aluminum in an acidic aqueous electrolyte comprising sulfuric acid, a polyhydric alcohol of from 3 to 6 carbon atoms and an organic polycarboxylic acid containing at least one reactive group in the alpha-position coloring the coating by applying alternating current to an electrode system comprising the coating and a counterelectrode immersed in an acidic aqueous bath containing a metal salt while modulating the voltage externally of said electrode system so as to apply voltage with controlled asymmetry to said electrodes.</p> |
