The Synergism Effect of Cerium Chloride and Nickel Sulphate on the Corrosion Resistance Behaviour of Zirconium Conversion Coating on Steel Substrate

In this paper, the effect of cerium chloride with solution features of immersion time=۱۵ minutes, concentration of cerium=۵ gr/lit, pH =۵.۵ at room temprature  on the anti-corrosion behaviour of zirconium- coated steel in optimized condition with immersion time = ۹۰ seconds,۰.۰۱ molar H۲ZrF۶ and pH= ۴ was investigated.The results of EIS test showed that the corrosion resistance of steel without coating, with zirconium conversion coating and with zirconium-cerium conversion coating was ۵۲۰, ۱۱۵۰ and ۲۴۰۰ Ω/cm ۲ respectively. DC polarization test showed that the corrosion current density decreasd from ۸.۲ to ۱.۶ µA/cm۲ .The addition of ۲۰۰ ppm nickel sulphate to the cerium conversion solution increased the corrosion resistance of Zr-modified steel to ۳۳۰۰ Ω/cm ۲ .

کلیدواژه ها:

Corrosion ، Conversion coating ، Hexaflourozirconic acid ، Cerium ، Electrochemical impedance spectroscopy ، Direct current polarization ، خوردگی ، پوشش تبدیلی ، هگزافلوئوروزیرکونیک اسید ، سریم ، طیف سنجی امپدانس الکتروشیمیایی ، پلاریزاسیون جریان مستقیم ،