Study on the Corrosion Properties of Cerium Conversion Coating for AZ31B Magnesium Alloy

• Main Authors: LIU,TZU-CHIAO, 劉子僑
• Other Authors: M.S. Yeh
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/71501368627335430433

碩士 === 中華大學 === 機械工程學系碩士班 === 99 === The corrosion behavior of a cerium conversion film formed on the AZ31B magnesium alloy has been evaluated in 3.5 wt. % NaCl solution by polarization testing in this study. Before the conversion coating process, the AZ31B magnesium substrates were pickled in different acids, such as sulfuric acid, nitric acid, and phosphoric acid. Experimental results showed that the thickness of cerium oxide film on the substrate increased with increasing the conversion coating time. After sulfuric acid picked and then immersion in cerium salt solution 20 minutes, the AZ31B magnesium substrates possesses the most noble corrosion potential and the lowest corrosion current density. Moreover, the surface morphology of the corroded samples was also investigated by a scanning electron microscope (SEM).