基于扫描式阴极的TC4合金微弧氧化行为研究  

Micro-arc Oxidation Behavior of TC4 Alloy Based on Scanning Cathode

作　　者：王小龙 孙祚东 朱辰 

机构地区：[1]中国特种飞行器研究所结构腐蚀防护与控制航空科技重点试验室,湖北荆门448035

出　　处：《表面技术》2017年第5期47-51,共5页Surface Technology

摘　　要：目的以磷酸盐为氧化槽液体系,在TC4合金大尺寸平板件表面获得均匀连续、无印痕的微弧氧化膜层。方法设计封闭和半封闭式扫描阴极开展氧化试验,研究不同的封闭方式对钛合金微弧氧化膜层的影响,以确定阴极的封闭形式。对试件进行微弧氧化并通过SEM/EDS检测膜层的形貌和成分。结果全封闭式阴极可有效避免弱电场对膜层的影响。半封闭阴极的开口宽度和密封方向对微弧氧化膜有影响,在开口方向,电场辐射区约150 mm,膜厚随距阴极距离的增加而递减,在阴极宽度1倍处,膜厚稍有衰减,其影响区为阴极宽度的6倍。若阴极两端均不密封,氧化影响区将是阴极宽度的12倍。结论采用前部适度敞开、后部彻底封闭的阴极构形,可控制氧化过程中由于电场强度变化引起的膜层脱落和烧蚀缺陷,获得连续均匀的微弧氧化膜。氧化工艺参数可设置为电压450 V,脉宽15,脉数500,扫描速度10 mm/min。The work aims to obtain uniform, continuous and print-free micro-arc oxidation coatings on the surface of large-size TC4 alloy fiat workpieces in the oxidation bath system of phosphate. Fully-closed and semi-closed cathodes were de- signed to perform oxidation test, and effects of different sealing methods on micro-arc oxide coating on titanium alloy were stu- died to determine final cathode sealing form. Specimens were subject to microare oxidation, and morphology and composition of the coatings were detected with SEM/EDS. The fully-closed cathode could effectively avoid effects of weak electric field on the coatings. MAO coatings were affected by opening width and sealing direction of the semi-closed cathode. In the direction of opening, radiation area of the electric field was about 150 mm, the coating thickness decreased with the increase of the distance from the cathode. Thickness of the coatings attenuated slightly at 1 time of the cathode width, and the influence area was about 6 times of the cathode width. The influence area of oxidization would be 12 times of the cathode width if the cathode was not sealed on both ends. The cathode structure featuring in moderately opened forepart and fully-closed rear can control film falling off and ablation defect caused by change of the electric field intensity during the oxidation process, and continuous and uniform micro-arc oxide film is obtained. Oxidation process parameters can be set as voltage of 450 V, pulse width 15, pulse number 500 and scanning speed 10 mm/min.

关 键 词：微弧氧化 封闭式阴极 半封闭式阴极 TC4合金大尺寸平板件 弱电场 烧蚀 

分 类 号：TG174.44[金属学及工艺—金属表面处理]