Investigation of Anti-Corrosion Resistance and Morphology of Titanium/Zirconium Conversion Coating on AL-۲۰۲۴ Alloy

In this research, the anti-corrosion resistance of titanium/zirconium based conversion coating on Al-۲۰۲۴ substrate was investigated. Ti/Zr solution practical parameters such as acids concentrations(۱, ۵, ۱۰ g/lit) solution pH (۳, ۴, ۵), and immersion time (۱, ۳, ۵ min) were optimized Obtained result from DC (Direct polarization) and EIS (Electrochemical Impedance Spectroscopy) revealed that Ti/Zr conversion coating with the acid concentration of ۱ g/lit for both H۲ZrF۶ and H۲TiF۶ solution pH equal to ۴ and immersion time of ۳min had the highest anti-corrosion performance. Corrosion current density and low frequency impedance values for untreated substrate are ۴۸.۱ µA/cm۲ and ۱۴۳۹ ohm.cm۲ respectively. These values for optimized Ti/ Zr conversion coating are ۶.۱ µA/cm۲ and ۴۲۰۶ ohm.cm۲. Also, field emission scanning electron microscope (FE-SEM) and atomic force microscope (AFM) images indicated the presence of fine and compact particles on the surface of Ti/Zr treated substrate

کلیدواژه ها:

Corrosion ، Titanium/Zirconium Conversion Coating ، Electrochemical impedance spectroscopy ، Field emission scanning electron microscope ، Atomic force microscope ، پوشش تبدیلی تیتانیوم/زیرکونیوم –طیفن سنجی امپدانس الکتروشیمیایی- میکروسکوپ الکترونی گسیل میدانی – میکروسکوپ نیروی اتمی