Anticorrosive Behavior and Porosity of Tricationic Phosphate and Zirconium Conversion Coating on Galvanized Steel

Aluminum Protection by Using Green Zirconium Oxide Layer and Organic Coating: An Efficient and Adherent Dual System

“…The coating porosity (P), after the metal bare pre-treatment with alkaline degreasing solution and after the formation of zirconium oxide coating, was evaluated following the procedure described by previous authors (Equation ( 1)) [2,40,41]:…”

“…Tricationic phosphating renders a basic level of corrosion protection and, usually, the thickness of the conversion coating is optimized by adding oxidants like molybdate, chlorate, organic nitro compounds, among other accelerators, in the phosphate bath [1]. Altogether result in a huge increase of sludge with hazardous contaminants for water effluents and elevated costs for waste recovery [2]. By other hand, since the implementation of REACH regulation in 2006 [3], chrome plating process has been eliminated as chemical passivation pretreatment in galvanized structures due to its technically proven hazardous to human health and environment [4].…”