Preparation Process Aluminum Alloy Micro-arc Oxidation Ceramic Layer And The Ceramic Layer Growth Process

The process formulae, which constituents played important roles in growthprocedure and properties of ceramic coating as principles were discussed, suchsolutions as Phosphate, silicate and carbonate systems and technology of Micro-arcOxidaion on Aluminum alloy and the influencing factors of Micro-arc Oxidationceramic coating growth, which characteristics were observed by SEM, weresystematically investigated using contrast and orthogonal methods. The phasestructures and elements distributions varied in different thickness were shown by XRDand EPA. The wear-resistance characteristics of micro-arc oxidaion ceramic coatingwere also analyzed.The results indicated that at beginning of ceramic coating growth the alumnaceramic grains were formed at self-oxidizing defects and then were vertical tosubstrate to grow as column, then overlaPPing molting and sintering and depositingwith increase of thickness as its growth features, ceramic coating were made up of α─Al₂O₃, γ─Al₂O₃ and amorphous which content with different process technologyand thickness were different. It was found that there were constituent elemots inprocess solutions of ceramic coating, but the element distribution in different thicknesswere divergent due to similarities and differences of adsorption and transmissioncapability. The formulae and its constituents, currnt density frequency and theincrease of voltage pattem had to some extent influence on growh and properties ofceramic coating. Based on better formulae as phosphate, silicate and carbonate processsolutions, much better S-56 formulae and process were found. At steady wear phase,the wear resistance properties of micro-arc oxidaion ceramic coating were more betterthan that of coatings of chromium-plating and thermal spraying alumna.