氧化时间对7A55铝合金微弧氧化膜的影响

Effect of Oxidation Time on Micro-arc Oxidation Ceramic Coatings Formed on 7A55 Aluminium Alloy

采用恒流微弧氧化法在碱性硅酸盐-磷酸盐体系电解液中对7A55铝合金进行了微弧氧化处理,研究了氧化时间对微弧氧化膜表面形貌、厚度和相组成的影响。研究结果表明,在恒定的电参数(电流密度为6A/dm2,占空比均为30%,频率为1000Hz)条件下,随着氧化时间的延长,阳极电压逐渐增大,氧化膜表面微孔孔径逐渐增大,微孔数量逐渐减少,膜层厚度随氧化时间近似呈线性增加;膜层主要由γ-Al2O3相组成。

Ceramic oxide coatings were formed on 7A55 aluminium alloy surface by micro-arc oxidation （MAO） at the constant current density of 6A/dm^2 in Na2SiO3-NaOH-（ NaPO3 ）s solution. The effects of oxidation time on surface microphologies, thickness and phase composition of the micro-arc oxidation coatings were investigated. The results indicate that with increasing oxidation time, anodic voltage increases gradually and the number of mieropores of the MAO coatings decreases while the size of the mieropores increases with constant electrical parameters （ i = 6A/dm^2 , D = 30% and f= 1000Hz）. The thickness of the coatings increases lineally with oxidation time increasing. The MAO coatings is mainly composed of γ-Al2O3.