摘要
在硅酸盐体系(Na_2SiO_3+KOH)电解液中,采用微弧氧化技术在5052铝合金表面原位生成微弧氧化膜层。并利用SEM、EDS和XRD等仪器设备,分析微弧氧化膜层形貌、元素分布和相组成,着重分析氧化时间对膜层厚度、表面孔隙率和最大孔洞直径及膜层耐腐蚀性的影响。结果表明:微弧氧化膜层表面有典型的"火山堆积"形貌生成,且膜层厚度、表面孔隙率和最大孔洞直径随氧化时间的增加而增大;膜层主要元素为O和Al,相组成为γ-Al_2O_3和α-Al_2O_3,且主要为γ-Al_2O_3;微弧氧化处理可显著提高试样的耐腐蚀性能,腐蚀电流密度至少下降2个数量级,电化学阻抗模值|Z|至少增加2个数量级,随氧化时间从10 min延长到50 min试样的耐腐蚀性能先提升后降低,氧化时间为20 min的试样耐腐蚀性能最好。
Micro-arc oxidation(MAO)films were fabricated on 5052 aluminum alloy by micro-arc oxidation in silicate system(Na2SiO3+KOH)solution.The morphology,elemental distribution and phase composition of MAO films were analyzed by scanning electron microscope(SEM),energy dispersive spectroscopy(EDS)and X-ray diffraction(XRD).The effects of oxidation time on the film thickness,surface porosity,the maximum hole diameter and the corrosion resistance of the film were analyzed emphatically.The results show that the surface of the micro-arc oxidation film has“volcano deposit”morphology,and the film thickness,surface porosity and pore diameter increase with increasing oxidation time.The film mainly with O and Al elements,is composed ofγ-Al2O3 andα-Al2O3 phases,in which the content ofγ-Al2O3 phase is higher.The corrosion resistance of MAO treated sample is obviously improved,the corrosion current density is decreased by at least two order of degree magnitude,and the electrochemical impedance modulus|Z|is increased at least two order of degree magnitude.With the oxidation time increasing from 10 min to 50 min,the corrosion resistance of the sample first increases and then decreases.When the oxidation time is 20 min,the sample shows the best corrosion resistance.
作者
方雷
马运柱
刘文胜
刘阳
刘超
颜焕元
FANG Lei;MA Yunzhu;LIU Wensheng;LIU Yang;LIU Chao;YAN Huanyuan(State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083)
出处
《粉末冶金材料科学与工程》
EI
北大核心
2018年第5期503-510,共8页
Materials Science and Engineering of Powder Metallurgy
基金
国家重点基础研究发展规划资助项目(61xxxx02)
关键词
5052铝合金
微弧氧化
氧化膜
膜层结构
耐腐蚀性
5052 aluminum alloy
micro-arc oxidation
oxidation film
film structure
corrosion resistance
