AZ91D镁合金α、β相上微弧氧化膜的生长特点  

Growth feature of micro-arc oxidation coating on α and β phase of AZ91D magnesium alloy

作　　者：马颖[1] 王兴平 安凌云 孙乐[1] 董海荣[1] 王占营[1] MA Ying;WANG Xing-ping;AN Ling-yun;SUN Le;DONG Hai-rong;WANG Zhan-ying(State Key Laboratory of Advanced Processing and Recycling of Nonferrous Metals,Lanzhou Univ.of Tech.,Lanzhou 730050,China)

机构地区：[1]兰州理工大学省部共建有色金属先进加工与再利用国家重点实验室,甘肃兰州730050

出　　处：《兰州理工大学学报》2018年第5期1-6,共6页Journal of Lanzhou University of Technology

基　　金：甘肃省创新研究群体计划基金(1111RJDA011)

摘　　要：在硅酸盐体系电解液中,在不同电压下对AZ91D镁合金进行微弧氧化处理,研究微弧氧化过程中基体中所含α-Mg和β-Mg17Al12相组成物上微弧氧化膜的生长特点.分析了膜层的微观结构、元素分布及相组成.结果表明:微弧氧化膜形成初期,尽管β相上先于α相生成无击穿微孔的氧化膜,但击穿却首先在α相表面发生,使得有击穿微孔的微弧氧化膜首先在α相表面形成,再逐渐扩展到整个基体表面.基体α、β相上Mg、Al元素摩尔分数的差异,使得所成微弧氧化膜中Mg、Al、O在膜层表面的分布都不均匀,但随着膜层厚度的逐步增大,3种元素的分布逐渐均匀化,而Si、F元素的分布始终比较均匀.因此,基体中不同的相组成物主要影响微弧氧化的初期成膜过程,而对膜层形成后的长大过程影响不大,当工作电压为250V时,获得了表面元素分布较为均匀的膜层.AZ91D magnesium alloy was processed by micro-arc oxidation(MAO)in silicate-series electrolyte under different voltages and the growth feature of MAO coating on two phase compositions ofα-Mg andβ-Mg 17 Al 12 in the substrate during MAO process was investigated.The microstructure,element distribution and phase composition of the coating were analyzed.The result indicated that at the initial stage of the formation of MAO coating,although,the oxide coating without break through micro-pores would appear on the surface ofβ-phase prior toα-phase,the break through,however,would occur on the surface ofα-phase first,making the MAO coating with break-through micro-pores to form first on the surface ofα-phase and then to expand gradually onto entire surface of the substrate.The content difference of elements magnesium and aluminum betweenα-phase andβ-phase in the substrate would lead to uneven content distribution of elements magnesium,aluminum and oxygen on the coating surfaces during the initial stage of the MAO process.The content distribution of the above three elements,however,would gradually homogenize with the increase of MAO coating thickness.Nevertheless,the distribution of elements silicon and fluorine on the coating surface would keep almost uniform during whole MAO process.Therefore,α-andβ-phase contained in the substrate would exhibit significant influence in initial coating forming stage during MAO treatment but less effect on the coating growth process later on after the coating being formed.An MAO coating with homogenized surface element distribution would be obtained when the working voltage was 250 V as shown in this investigation.

关 键 词：镁合金 微弧氧化 基体相组成物 膜层生长 

分 类 号：TG174[金属学及工艺—金属表面处理]