摘要
为了系统了解微弧氧化电参数对铝合金微弧氧化膜耐蚀性的影响,采用自制的设备以恒流法在硅酸盐系电解液中对LY12铝合金进行微弧氧化处理。研究了频率、占空比、时间等参数对铝合金微弧氧化陶瓷层电化学腐蚀行为的影响。用扫描电镜(SEM)和电化学工作站等手段,分析了不同能量参数制备的陶瓷层的微观结构及耐蚀性。结果表明:随着频率增加,陶瓷层的腐蚀电位正移、腐蚀电流密度下降,阻抗值变大,耐蚀性变好;随占空比增大,陶瓷层的耐蚀性变差;随着氧化时间延长,陶瓷层明显变粗糙;随着膜厚增加,陶瓷层的腐蚀电位正移,腐蚀电流密度下降,阻抗值变大,陶瓷层对基体的保护作用增强。
A home-made micro-arc oxidation(MAO) facility was performed in constant current mode to prepare ceramic coatings on LY12 Al alloy from silicate electrolyte.The microstructure and corrosion resistance of the MAO coatings obtained under different parameters were analyzed using a scanning electron microscope and an electrochemical workstation,and the effects of frequency,duty cycle and time on the electrochemical corrosion behavior of the MAO coatings were investigated.Results indicate that increasing frequency leads to positive shift of the corrosion potential of the ceramic coatings,decreased corrosion current density,increased impedance and increased corrosion resistance.The corrosion resistance of the ceramic coatings decreased with increasing duty cycle,and their surface roughness increased with extending oxidation time.Besides,increasing thickness led to positive shift of the corrosion potential of the ceramic coatings,decreased corrosion current density,increased impedance and better protection for the Al alloy substrate.
出处
《材料保护》
CAS
CSCD
北大核心
2011年第6期11-13,4,共3页
Materials Protection
基金
国家"十一五"科技支撑计划项目(2008BAE-63B00)
陕西省重点学科建设专项资金资助项目
关键词
微弧氧化
LY12铝合金
陶瓷层
耐蚀性
极化曲线
电化学阻抗
micro-arc oxidation
LY12 aluminum alloy
ceramic coating
corrosion resistance
polarization curve
electrochemical impedance
