微弧氧化非连续成膜对膜层结构及性能的影响

Effect of discontinuous micro-arc oxidation on structure and properties of fabricated coatings

在含有Na2SiO3和KOH的电解液中以恒定电压氧化方式对工业纯铝进行微弧氧化处理,研究电压对非连续微弧氧化成膜特性的影响。采用XRD及SEM对微弧氧化膜的相组成及表面形貌进行分析。结果表明:非连续微弧氧化的电流在工作间隔处出现一定程度的降低;非连续工作模式的膜层生长速率与连续模式基本相同,并且都随工作电压的增加而增加;不同成膜模式所生长的微弧氧化膜均由较多的γ-Al2O3和少量的α-Al2O3相组成;非连续成膜方式对微弧氧化陶瓷膜的形貌影响不大,且未造成氧化膜分层现象;不同成膜模式下所形成的微弧氧化陶瓷层的耐磨性能和耐腐蚀性能随工作电压变化具有相同的变化规律,均随电压的增加而增大;非连续成膜提高了微弧氧化控制的灵活性。

Pure aluminum was treated by micro-arc oxidation in electrolyte containing Na2SiO3 and KOH at constant voltage mode.The effect of voltage on the properties of the coating prepared by discontinuous micro-arc oxidation was investigated.The phase composition and surface morphologies of MAO coatings were analyzed by XRD and SEM.The results show that,for the discontinuous MAO,the current drops to some extent at the interrupted point.MAO coatings fabricated by different modes show the similar thickness that increases with increasing oxide time.The processing mode has slight effects on the phase composition of MAO coatings,which are mainly composed of γ-Al2O3 and α-Al2O3.The surface morphology of the MAO coatings is hardly influenced by processing mode and no lamination is observed for the coatings prepared by discontinuous mode.The coatings fabricated by different modes possess the similar changing rules of wear resistance and corrosion resistance.This discontinuous mode improves the control flexibility during micro-oxidation processes.