The effect of pre-immersing after electropolishing on the anodic film properties and electrolytic coloring ofaluminum

• Main Authors: Yu-min Chen, 陳育民
• Other Authors: Hsing-hsiang Shih
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/21925208113266747847

碩士 === 大同大學 === 化學工程學系(所) === 98 === Aluminum due to high activity and light weight, good gloss, high electrical conductivity and thermal conductivity, it is widely applied in industry and our life. At present, many studies are looking a process to form a dense film on aluminum. This study adopts three different process before the anodizing treatment, one is the convrtional pretreatment,another is the polished treatment before anodization,the other is preimmersing in the ammonium molybdate before anodization.The polishing method has the advantage of reaching the surface leveling, gloss and smoothing to form the anodic film. Using the surface modifier of ammonium molybdate, a molybdenum oxide film would cover the aluminum surface, it can make the anodic process slowly and steadily to build a more dense film more hard oxide film. It was found that the use of polished anodized aluminum can make more holes and a larger aperture, but the structure is loose, the use of pre-immersing step to improve the corrosion resistance and hardness that decreased by the polished process. Though the immersing after polishing process can obtain a anodic film with better durability, but the Cu-coloring is with difficuty, the drawback can be overcomed by using AgNO3 for coloring, it can obtain the darker black film with hardness of 419.9Hv and ΔE* of 9.8 at 3A/dm2. While the single polishing process can obtain the blackest film with ΔE* of 6.53 at 2A/dm2 but it’s hardness drops to 312.3Hv.