电流密度对铝合金微弧氧化膜的生长及结合力的影响  

Effect of Current Density on Growth and Adhesion of Micro-Arc Oxidation Ceramic Coatings on Aluminum Alloy

作　　者：魏同波[1] 张学俊[1] 王博[1] 田军[1] 阎逢元[1] 

机构地区：[1]中国科学院兰州化学物理研究所固体润滑国家重点实验室,甘肃兰州730000

出　　处：《材料保护》2004年第4期4-6,共3页Materials Protection

基　　金：国家自然科学基金(50271080)

摘　　要：为了进一步探讨微弧氧化主要参数电流密度对铝合金微弧氧化膜的影响机理,先用微弧氧化技术在LY12硬铝合金上获得陶瓷层,然后考察电流密度对陶瓷膜厚度及其与基体结合强度的影响,再利用扫描电镜(SEM)、X射线衍射(XRD)、光电子能谱(XPS)分析了氧化膜的形貌和组织结构,通过划痕试验和冲击试验研究了氧化膜与基体的结合力。结果表明,随着电流密度的增大,陶瓷氧化膜及其致密层的增长速度均加快,但有一个极限值,氧化膜的临界载荷降低,致密层所占比例也逐渐降低。XPS谱图证明,微弧氧化膜表面疏松层主要由γ-Al_2O_3,α-Al_2O_3和Al-Si-O相组成,致密层由α-Al_2O_3和γ-Al_2O_3组成。铝合金表面生成氧化膜后,随着膜厚度的增加,冲击韧性逐渐减低,基体断裂后,氧化膜没有发生剥落,表面出现大量微裂纹。Ceramic coating was obtained on LY12 aluminum alloy by micro-arc oxidation. The influences of current density on the thickness and adhesion strength of ceramic coating were studied, and the morphology and structure of micro-arc oxidation coatings were investigated by using SEM. XRD and XPS. The adhesion of oxidation coating to substrate was evaluated through scratch test and impact test. It is found that the growth velocity of oxidation coating and its dense layer increases with the increase of current density, while there is a limit value. On the other hand, the critical load of oxidation coating and the thickness ratio of dense layer in oxidation coating decrease with the increase of current density. The superficial loose layer is mainly composed of γ- Al_2O_3 , α-Al_2O_3 and Al-Si-O phase, but mostly α-Al_2O_3 and γ-Al_2O_3 in the dense layer according to XPS spectra. Impact toughness of aluminum alloy with oxidation coating gradually decreases with the increase of coating thickness. After the substrate is break, oxidation coating is not stripped from the alloy substrate, while a large number of cracks occur on the surface.

关 键 词：微弧氧化 铝合金 陶瓷膜 结合强度 电流密度 

分 类 号：TG174.451[金属学及工艺—金属表面处理]