Effect of Current Mode on the Hardness, Corrosion Behavior and Morphology of the Nanostructure Anodized Aluminum Coatings

In the present work, effect of current mode on the hardness, corrosion behavior and morphology of the aluminum anodized coatings is studied. In order to take the effect of current mode on the properties of anodized coatings into consideration, different current modes, i.e. direct current, direct current plus pulse, positive and negative pulse and single pulse were applied. Microhardness tests and polarization measurements were conducted to investigate the mechanical and corrosion properties of anodized coatings. Results show that the hardness of anodized coatings fabricated by direct current mode is lower than those in pulse current mode. Also, the corrosion study of samples treated at various current modes showed that the corrosion current density of the sample anodized by pulse current mode is ۲۵۰۰ times lower than the samples processed by DC current mode (۲۵۰۰ times higher than . Also, FE-SEM micrographs showed pore diameter of the coatings anodized by pulse current mode is smaller than the other samples. The small pore diameter of the coatings anodized by pulse current mode can be due to decreasing in temperature on the surface of anodized coatings.

کلیدواژه ها:

Aluminum Anodizing ، Pulse current ، Surface Morphology ، Vickers Microhardness ، Corrosion behavior ، آندایزینگ آلومینیوم ، جریان پالسی ، مورفولوژی سطحی ، سختی ویکرز ، مقاومت به خوردگی.