镁合金微弧氧化Na_2CO_3诱导析气反应及结构调制  

Na_2CO_3-induced Gas Evolution Reaction and Morphology Modulation on Magnesium Alloy during Micro-arc Oxidation

作　　者：王晓波[1] 田修波[1] 巩春志[1] 杨士勤[1] 

机构地区：[1]哈尔滨工业大学现代焊接生产技术国家重点实验室,哈尔滨150001

出　　处：《无机材料学报》2011年第7期721-725,共5页Journal of Inorganic Materials

基　　金：国家自然科学基金(10775036)~~

摘　　要：阳极析气能够有效调制微弧氧化膜层表面形貌.实验提出了一种CO2增强析气的方法.在Na3PO4+KOH+NaF溶液中添加Na2CO3对AZ31镁合金表面进行微弧氧化处理.利用气相质谱、扫描电镜、X射线衍射、红外光谱扫描探讨了Na2CO3添加剂对阳极区析气反应的影响和对膜层形貌、结构的调制作用.结果表明:与传统微弧氧化不同,添加Na2CO3之后,阳极区产生的气体既有O2也有CO2.在含Na2CO3的电解液中,微弧氧化前期的阳极氧化阶段有MgCO3生成;在微弧氧化后期,膜层中不含有MgCO3,膜层主要相仍为MgO相.对比发现,经过Na2CO3调制之后的膜层表面大尺寸孔隙数目减少,膜层孔隙率提高.Surface morphology of the ceramic coatings can be modulated by gas evolution on anodes during micro arc oxidation（MAO） processes.A novel technique to enhance gas evolution using Na2CO3-containing solution was proposed.MAO ceramic coatings were fabricated on AZ31 magnesium alloy using Na2CO3 as a special additive in Na3PO4＋KOH ＋NaF base electrolyte.The effects of Na2CO3 addition on the reaction of gas evolution near the an-ode,morphology modulation and chemical composition were investigated by using GC-MS,SEM,XRD and FTIR,respectively.The results show that both O2 and CO2 are evolved from the anode with Na2CO3 addition during MAO process.MgCO3 is found in the coating during the anodic oxidation before MAO,while only MgO is detected in the coating after MAO process.It is attributed to the decomposition of MgCO3 to MgO and CO2 due to local high tem-perature.Na2CO3 addition has slight effect on the microstructure of the coating and MgO is the main phase no mat-ter whether Na2CO3 is utilized.With the addition of Na2CO3 the number of larger-size pores decreases and porosity in the coatings increases.

关 键 词：微弧氧化 析气 镁合金 NA2CO3 调制作用 

分 类 号：TG174[金属学及工艺—金属表面处理]