Preparation and Characterization of Sol-Gel Coatings Doping with Cerium Ingredients on Aluminum Alloy Surface

In order to improve the corrosion resistance of aluminum alloys, a way of preparing an environmental friendly sol-gel coatings free of element Cr with the ingredients of rare earth Ce compound was investigated. The effects of Ce ingredients on the formation of sol solution were studied and a discussion on influential factors of each technique was carried out. Meanwhile, a thorough inducement of studies on characterization of sol-gel coating's micro structure as well as anti-corrosion properties was illuminated. All the results indicated that the Ce ingredients in sol solution was favorable for a uniform formation of surface coating and made it easier for the sol solution adhere on aluminum alloy substrate. Because of the wetting and activation ability of rare earth elements, the coating with Ce additives was 0.71 μm thicker than those without Ce additives. Ce alleviated the exothermal reaction during the formation of coatings, thus reformed the density and cohesion with substrates of coatings. Such coatings were able to isolate the substrate form contacting the corrosive media and consequently protected the alloy from being corroded efficiently.