铝箔阳极氧化后2种铈转化膜的沉积机理

Mechanisms of Formation of Cerium Conversion Films on Anodized Aluminum

为探讨铝阳极氧化沉积铈转化膜形成机理,分别用化学沉积和电沉积法在铝阳极氧化膜上制备了铈转化膜。用SEM和EDS表征了阳极氧化膜、化学沉积铈转化膜和阴极电沉积铈转化膜的形貌和组分,测试了膜层厚度和膜的耐腐蚀性。结果表明:平均孔径89nm的铝阳极氧化膜经阴极电沉积、化学沉积铈后平均孔径分别减小为38nm和32nm,2种沉积分别可得到含铈52.10%和20.39%的铈转化膜。2种铈转化膜的平均膜厚分别比铝阳极氧化膜的大1.96μm和1.23μm,极化电阻均是铝阳极氧化膜的近3倍。2种铈转化膜形成机理不同是造成它们性质不同的原因。

Cerium conversion films were prepared on anodized aluminum via chemical deposition and electrodeposi-tion respectively,and the mechanisms of formation of the cerium conversion films were investigated.The morphology and demental composition of the two types of cerium conversion films and alu-minum anodized coating were analyzed by means of scanning elec-tron microscopy and energy dispersive spectrometry.And the thickness and corrosion resistance of the cerium conversion films were measured.Results show that the average pore size of the aluminum anodized coating is reduced from 89 nm to 38 nm and 32 nm after cathode electrodeposition and chemical deposition.The resulting cerium conversion films on the aluminum anodized coating have a cerium content of 52.10% and 20.39%,respec-tively.Moreover,the average thickness of the two types of cerium conversion films is larger than that of the aluminum anodized coating by 1.96 μm and 1.23 μm,and their polarized resistance is almost three times as much as that of the aluminum anodized coating.In general,the different properties of the two types of cerium conversion films are closely related to their different mech-anisms of formation.