Advances in conversion coatings

The oxidation and degradation of metals is a serious and costly problem. To prevent the oxidation and degradation of metals, inorganic conversion coatings are applied to the metalʹs surface. Currently, chromate based coatings are used as conversion coatings in many industrial settings because they impart corrosion resistance. However, hexavalent chromium is toxic and carcinogenic. Therefore, there is a need for a conversion coating that can replace chromate based conversion coatings. The aim of this article is a brief overview of less toxic conversion coatings based on rare earth compounds, Zirconium, Titanium, vanadium, molybdenum and Silicon. As well as, Recently composite conversion coatings containing nanoparticle have been studied due to their excellent anticorrosion properties. Therefore This paper reviews the recent researches that has been conducted on composite conversion coatings.