A3钢热浸镀铝层微弧氧化复合转化层的微观组织特性

Microstructure Characteristics of Hot-Dip Aluminum and Micro-arc Oxidation Multilayer Conversion Coating on A3 Steel

利用热浸镀铝、微弧氧化复合工艺,在A3钢板表面上制备出多层结构的转化层。利用扫描电镜技术(SEM)对复合转化层形貌进行观察,并结合能谱分析仪(EDS)对内部组成元素的分布及原子个数比开展半定量分析,确定转化层内部的物质组成。分析结果表明:复合工艺处理后的A3钢板基体表面转化层具有三层结构:Fe-Al合金层—纯铝层—Al2O3陶瓷层;最内层的Fe-Al合金层呈枝晶状交错伸入铁基体中,最外层的Al2O3陶瓷层呈疏松多孔状结构,纯铝层均匀分布在二者之间;三层结构之间存在稳定的过渡层,各层之间结合牢靠。

By combined process of hot-dip aluminum and micro-arc oxidation, a multilayer conversion coating was obtained on the surface of A3 steel-plate. The micro-morphology and chemical elements of the coating were investigated by the means of scanning electron microscopy （SEM） and energy-dispersive spectrometry （EDS）. The construction of the coating was researched by the semi-quantitative analyses of atomic ratio. The results show that the multilayer coating obtained on the A3 steel-plate can be divided into three layers： Fe-Al alloy layer--pure aluminum layer Al2O3 ceramic layer; the innermost layer of branch-like Fe-Al which was grown into the iron substrate, the outermost layer of ceramic coating was a loose layer, and a pure aluminum layer was evenly distributed in the middle of them; there were stable intermediate coatings between the three layers, so the connection of them were reliable.