Novel tribological properties of anodic oxide coating of aluminum impregnated with iodine compound

• Published in: Surface & coatings technology Vol. 169; pp. 160 - 162
• Main Authors: Takaya, M., Hashimoto, K., Toda, Y., Maejima, M.
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 02-06-2003
• Subjects: Anodic oxide coating; Electrochemical impregnation; Friction; Iodine compound; Wear; Anodic oxide coating; Iodine compound; Electrochemical impregnation; Friction; Wear
• ISSN: 0257-8972; 1879-3347
• DOI: 10.1016/S0257-8972(03)00218-4

Several iodine compounds are well known as solid-state lubricants in the halogen family, however, satisfactory results of their use in the manufacturing industry have not been reported. Subsequently the anodic oxide coating of aluminum impregnated with iodine compound in the concrete inclusion complex with iodine was prepared successfully by an electrochemical method and tribological properties of obtained anodic oxide coating were investigated [Proceedings of INTERFINISH 2000 15th World Congress and Exhibition Congresshaus Garmish-Parten—Kirchen, (2000)]. Iodine compound was found in micro-pores as iodine (I) of 0.1 mass% and formed iodophor of an amorphous structure. The tribological properties of obtained anodic oxide coating were estimated by friction and wear testing. The yielded coefficient of dynamic friction of a sample with iodine compound was less than 0.1. Obtained anodic oxide coating impregnated with PTFE, namely TUFRAM. The coefficients of dynamic friction of obtained anodic coating ADC12 aluminum die casting or A6061 aluminum alloy have proved to be lower in comparison with thin-film Sn on anodic oxide coating by electroplating. From these results, the impregnation of iodine compounds in the micro-pores of anodic oxide coating has proved to lower the coefficient of dynamic friction. We think this phenomenon originates from the orthorhombic system and lamellar structures of the iodine compound used this time, which are well known as solid lubricants.