LY12铝合金微弧氧化陶瓷层的结构和性能

分析了LY12铝合金微弧氧化陶瓷膜的形貌、组成和结构,研究了氧化膜的硬度、与基体的结合强度以及在油润滑和干摩擦这两种条件下的摩擦学行为.结果表明,铝合金微弧氧化膜可分为疏松层和致密层,疏松层由α-Al2O3、γ-Al2O3以及Al-Si-O相组成,致密层由α-Al2O3和γ-Al2O3组成,致密层中α-Al2O3的含量远远高于疏松层.从表层到基体,微弧氧化膜的断面显微硬度先增大后减 小.微弧氧化膜与铝合金基体结合紧密.随着膜厚度的增加,氧化膜的临界载荷线性增加.氧化膜具有优良的抗磨性能,油润滑条件下的摩擦系数仅为干摩擦下的1/10.

Structure and wear--resistant properties of ceramic layer on LY12 Al alloy by micro--arc oxidation

The morphology, content and structure of microarc oxidation ceramic coatings produced on LY12 Al alloy have been investigated. The microhardness, adhesion to the substrate and friction behavior under dry friction and oil lubricating conditions were also measured. It is found the microarc oxidation coatings consist of the loose superficial layer and the inner dense layer. The two layers are composed of $\alpha$--Al$_{2}$O$_{3}$ and $\gamma$--Al$_{2}$O$_{3}$, while the Al--Si--O phase of high content is observed only in loose layer. The $\alpha$--Al$_{2}$O$_{3}$ content in dense layer is distinctly higher than that in loose layer. From the superficial layer to the substrate, the cross--section microhardness first increases and then decreases, reaching a maximum at a distance of 35 $\mu$m from the substrate/coating interface. The adhesion strength of microarc oxidation coatings to Al substrate is high and the critical load increases linearly with increasing the coatings thickness. The microarc oxidation coatings possess excellent antiwear properties, and the friction coefficient under oil lubricating condition is only 1/10 of that under dry friction.