镁合金表面复合膜的制备及其耐蚀性  

Preparation and corrosion resistance of composite coatings on magnesium alloy

作　　者：尚伟[1,2] 陈白珍[1] 石西昌[1] 温玉清[2] 黄安生[2] 

机构地区：[1]中南大学冶金科学与工程学院,湖南长沙410083 [2]桂林理工大学化学与生物工程学院,广西桂林541004

出　　处：《中南大学学报（自然科学版）》2011年第11期3256-3261,共6页Journal of Central South University:Science and Technology

基　　金：国家科技支撑计划项目(2006BAB09B04);广西教育厅资助项目(200911MS110)

摘　　要：利用溶胶凝胶技术在镁合金微弧氧化膜表面制备SiO2溶胶凝胶膜形成复合膜层。通过扫描电镜和能谱测试,分析膜层的表面形貌和成分。采用动电位极化曲线测试研究不同条件下复合膜的电化学性能。研究结果表明:SiO2溶胶凝胶膜的最佳沉积条件为浸涂次数3次,浸泡时间1 min,干燥温度80～100℃,干燥时间8 h,固化温度170℃,固化时间1 h。溶胶凝胶膜能够有效地封闭镁合金表面微弧氧化膜的微孔,形成均匀且较为致密的复合膜层。动电位极化曲线结果表明:复合膜比微弧氧化膜和镁合金基体具有更正的腐蚀电位(Ecorr)、更低的腐蚀电流密度(icorr)和更大的线性极化电阻(Rp),说明微弧氧化镁合金沉积溶胶凝胶膜后耐腐蚀性能有显著地提高,复合膜对AZ91D镁合金具有良好的防腐蚀作用。Composite coatings consisted of a MAO layer and a sol-gel layer were obtained on a magnesium alloy by micro-arc oxidation（MAO） and sol-gel technique.The surface morphologies and composition of the MAO coating and the composite coatings were analyzed by scanning electron microscopy（SEM） and energy dispersive spectrometer（EDS）.Potentiodynamic polarization curves were used to investigate the electrochemical properties of the composite coatings formed under different conditions.The results show that the optimum conditions are obtained as follows.Coated frequency is 3 times,soak time is 1 min,drying temperature is controlled within 80-100 ℃,drying time is 8 h,curing temperature and curing time are 170 ℃ and 1 h,respectively.SiO2 sol-gel film could effectively seal micropores in the MAO coating.The composite coatings are more uniform and compact than the MAO coating.The polarization result shows that the composite coatings have more positive corrosion potential（Ecorr）,lower corrosion current density（icorr）,and higher linear polarization resistance（Rp） than the MAO coating and magnesium alloy substrate,indicating that the sol-gel coating formed on the magnesium alloy with MAO coating under the optimum conditions has better corrosion resistance.The composite coatings have good protection to magnesium alloy AZ91D.

关 键 词：镁合金 微弧氧化 SIO2溶胶 复合膜层 耐蚀性 

分 类 号：O646[理学—物理化学]