Modification of chromate-free conversion coatings on 1105 aluminum alloy to increase their protective properties

Aluminum alloys, including alloys created on the basis of recycled metal, are widely used in various industries. Such alloys can differ in a significant range of the amount of alloying elements. 1105 aluminum alloy, which is made of recycled aluminum, contains Mg and Cu and it is characterized by a high content of other elements (Fe, Si, Zn). The intermetallics of these elements reduce the corrosion resistance of the alloy. Modern anti-corrosion techniques may help make 1105 alloy more widely available in a variety of applications. Among the various methods, conversion coatings obtained by chemical oxidation are a simple and economical way to protect against corrosion. The purpose of this work was to increase the protective properties of chromate-free IFKhANAL-3 conversion coatings by modifying them with nitrates and nitrites. One of the main problems of conversion coatings on aluminum 1105 alloy is their increased defectiveness at the micro level. The use of nitrate and nitrite compounds ensures more efficient formation of a conversion coating on the alloy surface, which makes it possible to enhance their corrosion resistance.