Structural and Electrochemical Properties of Al-Added Molybdate Conversion Coatings on Zinc

Abstract

Molybdate conversion coatings were deposited on zinc substrate in the presence of Al to improve the corrosion resistance and their structural and electrochemical properties were characterized with various analytical techniques. Infrared reflectance spectroscopy analysis indicated that Al existed as Al(OH)₃ in the molybdate conversion coatings. It was found that the addition of Al to molybdate conversion coatings hindered the oxygen reduction and hydrogen evolution reactions effectively compared with pure molybdate conversion coatings, resulting in the enhanced anticorrosive property.