The Investigation of Hot-Dip Aluminum and Micro-Arc Oxidation Multilayer Coating on 080A15 Steel

Abstract

By the combined process of hot-dip aluminum and micro-arc oxidation, multilayer ceramic coatings were obtained on the surface of commercial 080A15 steel plates. The microstructures and chemical elements of the coatings were investigated by means of scanning electron microscopy (SEM) and energy-dispersive spectrometry (EDS), respectively. The results show that the conversion coating on the surface of 080A15 steel plate is mainly composed of three layers, they are the outer layer of alumina ceramic coating, the middle layer of pure aluminum, and the inner layer of FeAl intermetallic compound. The FeAl intermetallic compound layer appears as branch-like to grow into the steel substrate. The alumina ceramic layer is a porous structure attached on the pure aluminum layer. The distribution of composition elements on the interface between the each layer is gradient transition, which is one of metallurgical adhesive characteristics.