Dr. Hongwei Shi, Environmental Corrosion Center, Institute of Metal Research, Chinese Academy of Sciences, Shenyang, China

Speech Title: Organic cerium salt-a new green inhibitor pigment for epoxy coatings on aluminium alloy

Abstract:For many years, protection of aluminium alloy relies on epoxy coatings containing chromate (Ⅵ) salts. However, due to the toxicity of chromates, their use is prohibited or progressively banned in industries. The development of chromate-free epoxy coatings attaches great importance. It is a big challenge to find environmentally benign inhibitor pigments replacing chromates. In the present work, a kind of novel inhibitor pigment, organic cerium salt, was synthesized and studied as a green inhibitor pigment in epoxy coatings. First, the effectiveness of two representative organic cerium salts, cerium cinnamate and cerium tartrate, were investigated. It was found that the two inhibitors are effective in corrosion inhibition on aluminium alloy 2024-T3. The protection mechanism during immersion in 0.05 M NaCl solution appears to involve two stages: the deposition of cerium salts, and then the hydrolysis of cerium ions forming a cerium oxide/hydroxide, prevailing over the foregoing deposition. Then, these inhibitor pigments were incorporated into the epoxy coatings and the corrosion resistance of the epoxy coatings was studied by electrochemistry impedance spectra (EIS) and scanning vibrating electrode technique (SVET). The results indicate that these green inhibitor pigments significantly improved the corrosion resistance of epoxy coatings on aluminium alloy 2024-T3. Also, the protection mechanism of the epoxy coatings containing organic cerium salts was analyzed.