Pulse-Reverse Polating to Prepare the Micro-Arc Oxidation film on AZ91D Alloy for Better Anti-corrosion Ability

• Main Authors: Heng-Jeng Li, 李衡政
• Other Authors: Wang S.S.
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/56022273059324004368

碩士 === 高苑科技大學 === 化工與生化工程研究所 === 98 === The oxide coating on AZ91D alloy was prepared to improve anti-corrosion property by pulse- reverse plating and micro-arc oxidation technique. In this study, the pulse-reverse plating formed a homogeneous micro-arc oxide layer that increased the hardness, thickness and corrosive resistance. The limit voltage of pulse plating potential is an important factor that affects the anti-corrosion character of oxide coating on AZ91D alloy. When the low-limit voltage is fixed as 40 V, the intensity of MgO crystalline peak shown on XRD pattern was increased with up-limit voltage increase that was change from 160 to 280 V and reached the maximum intensity at 240 V. In this study, the optimum conditions of plating solution were established as followed：2 M sodium hydroxide, 0.03 M sodium citrate, 0.06 M sodium tetraborate, 0.18 M tetramethyl ethylene diamine, 0.1 M phosphoric acid, 0.1 M sodium silicate and at 10℃. The best parameters for up-limit potential are 240 V and 50 ms, and 40 V and 50 ms for low-limit potential with 1000 times of duty cycles period. The corrosive resistance of oxide coating was increased when it had pre-treatment 10 min. The oxide film has passive potential of 12 V.