Plasma electrolytic oxidation behavior and corrosion resistance of brass in aluminate electrolyte containing NaH2PO4 or Na2SiO3  

黄铜在含磷酸二氢钠或硅酸钠的铝酸盐电解液中的等离子电解氧化行为和耐腐蚀性能

作　　者：Yu-lin CHENG Tian FENG Jia-hui LÜ Pan-feng HU Ying-liang CHENG 程昱琳;冯恬;吕佳慧;胡攀峰;程英亮(湖南大学材料科学与工程学院,长沙410082)

机构地区：[1]College of Materials Science and Engineering,Hunan University,Changsha 410082,China

出　　处：《Transactions of Nonferrous Metals Society of China》2022年第12期3985-3997,共13页中国有色金属学报（英文版）

基　　金：supported by the National Natural Science Foundation of China (No. 51671084);the Postgraduate Scientific Research Innovation Project of Hunan Province, China (No. QL20210092)。

摘　　要：Plasma electrolytic oxidation(PEO) of brass was carried out in aluminate electrolytes with the addition of NaH2PO4(S1) and Na2SiO3(S2), respectively, with the aim to investigate the effect of additives on the coating formation and corrosion resistance. For the PEO in S1 electrolyte, a mixed layer of AlPO4and Al2O3is formed at the initial stage, which leads to fast plasma discharges and formation of black coatings with the compositions of Al2O3,CuO, Cu2O and ZnO. However, in S2 electrolyte, plasma discharges are delayed and the coatings show a reddish color due to more Cu2O. Mott-Schottky tests show that the S1 coatings are p-type semiconductors;while the S2 coatings can be adjusted between n-type and p-type. Potentiodynamic polarization and electrochemical impedance spectroscopy(EIS) tests show that the PEO treatment can significantly improve the corrosion resistance of brass, with protection efficiency up to 91.50% and the largest charge transfer resistance of 59.95 kΩ·cm^(2) for the S1 coating.采用等离子电解氧化(PEO)技术对黄铜进行表面处理,研究其在铝酸盐电解液中分别加入NaH2PO4(S1)和Na2SiO3(S2)添加剂对涂层形成和耐腐蚀性能的影响。在S1电解液中进行PEO处理的初始阶段,黄铜表面形成AlPO4和Al2O3的混合涂层,导致快速产生等离子体火花放电现象并形成由Al2O3、CuO、Cu2O和ZnO组成的黑色涂层。然而,在S2电解液中,等离子体火花放电行为延迟产生。由于产生较多的Cu2O,S2涂层显示为深红棕色。Mott-Schottky测试表明,S1涂层为p型半导体;S2涂层具有n型和p型半导体可调性。动电位极化和电化学阻抗谱(EIS)测试表明,PEO处理能显著提高黄铜的耐腐蚀性,腐蚀防护效率可达91.50%,S1涂层电荷转移电阻最大可达59.95 kΩ·cm^(2)。

关 键 词：plasma electrolytic oxidation BRASS corrosion resistance ALUMINATE sodium dihydrogen phosphate sodium silicate 

分 类 号：TG174.4[金属学及工艺—金属表面处理]