To understand the formation and growth of plasma electrolytic oxidation(PEO) coatings in presence of different secondary phases in a substrate,PEO treatment was carried out on AlSi9 Cu3 alloy at different treatment ti...To understand the formation and growth of plasma electrolytic oxidation(PEO) coatings in presence of different secondary phases in a substrate,PEO treatment was carried out on AlSi9 Cu3 alloy at different treatment times ranging from 15 s to 480 s.The coating formation and evolution process was traced by surface and cross-sectional observation of the layers on the different phases of the alloy.The results demonstrated a sequential involvement of the different phases in the plasma discharges:firstly,discharges start on the α-Al matrix,then on the intermetallic Al2 Cu and β-Al5 FeSi phases at the same time and finally on the eutectic Si.The presence of intermetallic Al2 Cu remarkably affects the initial dissolution,the deposition of conversion products and the ignition of discharges at the early stages of processing.Eutectic Si in the substrate exhibits the highest electrochemical stability at all stages and contributes in the beginning to a distinct coating morphology eventually.The resultant PEO coating tends to be uniform if processing times are longer and a double-layer structure appears in the coating.展开更多
基金National Natural Science Foundation of China(No.52101084)Guangdong Basic and Applied Basic Research Foundation,China(Nos.2023A1515011579,2020A1515110754)Guangzhou Basic and Applied Basic Research Foundation,China(No.202102020612)。
基金the financial surpport from China Scholarship Council(CSC)。
文摘To understand the formation and growth of plasma electrolytic oxidation(PEO) coatings in presence of different secondary phases in a substrate,PEO treatment was carried out on AlSi9 Cu3 alloy at different treatment times ranging from 15 s to 480 s.The coating formation and evolution process was traced by surface and cross-sectional observation of the layers on the different phases of the alloy.The results demonstrated a sequential involvement of the different phases in the plasma discharges:firstly,discharges start on the α-Al matrix,then on the intermetallic Al2 Cu and β-Al5 FeSi phases at the same time and finally on the eutectic Si.The presence of intermetallic Al2 Cu remarkably affects the initial dissolution,the deposition of conversion products and the ignition of discharges at the early stages of processing.Eutectic Si in the substrate exhibits the highest electrochemical stability at all stages and contributes in the beginning to a distinct coating morphology eventually.The resultant PEO coating tends to be uniform if processing times are longer and a double-layer structure appears in the coating.
