LD10连接座表面铬酸阳极氧化白斑原因分析

摘要

Stereomicroscope observation, analysis of scanning electron microscopy & energy dispersive X-ray inspection, spot tests, etc. Were used for investigation of white spot phenomenon on anodic oxidation film of the submitted LD10 aluminum alloy connection block. The anodic oxidation film in the white spot area presented cracks, fragments, pitting and other morphological characteristics and also contained an abnormal mass fraction of chlorine element; threaded holes had typical characteristics of pitting corrosion, and contained corrosive media as well. The results show that the residual acid solutions in the threaded holes provide corrosive media to damage the oxide film and produce the white spots.%通过体视显微镜观察、扫描电镜及X射线能谱仪分析、点滴实验等检测手段对送检的LD10铝合金连接座表面铬酸阳极氧化膜层出现的白斑现象进行原因分析.表面白斑区域的阳极氧化膜层呈现出龟裂、破碎、脱落、点蚀坑洞等形貌特征,并含有异常质量分数的氯元素；连接座螺纹深孔内存在典型的点蚀特征,并含有外来的腐蚀介质元素.分析结果表明:螺纹孔内残留的酸性液体提供腐蚀介质,直接导致阳极氧化膜层的破坏以及表面白斑的产生.