Phosphate and stannate chemical conversion coatings formed on AZ91D alloys
The morphology and the mass change of the AZ91D alloys matrix after pretreatment, the morphology and the phase composition of chemical conversion coatings formed by phosphate and stannate were studied using scanning electron microscope, X-ray diffraction and the mass loss method. The corrosion resistance of the coatings were studied by salt spay test and damp heat test. The results show that the phase composition of matrix before and after pretreatment is almost changeless and the mass diminishes a litter, the deep micro flaw appears near between α-Mg and β phase during acidic pickling. The phosphate chemical conversion coating is mainly composed of Mg, MgO and some amorphous phase, and the stannate conversion coating is crystal structure and mainly composed of Mg, Al12Mg17 and MgSnO3·3H2O. Results from salt spay test and damp heat test indicate that the two coatings also can provide good protection for the magnesium alloy matrix, and stannate is better than phosphate.
Magnesium alloy Phosphate Stannate Chemical conversion coating Corrosion resistance
Xiangjie YANG Hualan JIN
School of Mechanical and Electronic Engineering, Nanchang University,Nanchang 330031, China School of Materials Science and Engineering, Nanchang University, Nanchang 330031, China
国际会议
重庆
英文
1407-1413
2008-06-09（万方平台首次上网日期，不代表论文的发表时间）