Anticorrosive Zr-containing Sol-gel Сoatings on AA5056 Aluminum Alloy

Due to the high toxicity of chromating solutions, which include highly toxic hexavalent chromium compounds, and the conversion coatings formed in them, laws have been adopted in most countries restricting or completely prohibiting the use of Cr(VI) compounds in mechanical engineering and electronics products. This publication is devoted to the development of the process of applying a protective sol-gel zirconiumcontaining coating to the surface of the aluminum alloy AA5056. The optimization of the process parameters for the deposition of a functional sol-gel coating was carried out, the physicochemical and mechanical properties of the coating, which could become an alternative to toxic chromate coatings, were investigated. During the work, it was found that the Zr-containing sol-gel coating is comparable in abrasion resistance to chromate films. The results of polarization measurements showed that the application of a multilayer sol-gel coating improves its protective ability. The increase in protective ability is also confirmed by exposure in the salt mist chamber. The time until the first signs of corrosion appear is 435 hours.