Effect of voltage on properties of microarc oxidation films prepared in phosphate electrolyte on Zr-1Nb alloy
A protective thin film on Zr-1Nb alloy was fabricated by AC microarc oxidation (MAO) in phosphate electrolyte. The morphology, microstructure and phase constituents of the MAO films under different discharge voltage were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Their surface roughness and microhardness were measured. The corrosion behaviors of films were evaluated by potentiodynamic polarization and electrochemical impedance spectroscopy (E1S). The equivalent circuits of EIS plots for bare Zr-1Nb alloy and MAO films were proposed. It was found that all of films at different discharge voltages consisted of the monoclinic ZrO2 and tetragonal ZrO2 phases, but the content of monoclinic ZrO2 was much higher than that of tetragonal ZrO2 phase. Microhardness of the MAO films is over 570 HV, which is much higher than that of Zr-1Nb alloy substrate with 245 HV. The film fabricated in higher voltage showed lower corrosion current density and higher impedance, which displayed better corrosion resistance. The EIS results identify that the compact inner layer of MAO films plays a key role on improving the corrosion resistance of Zr-1Nb alloy.
Microarc oxidation Zr-1Nb alloy Corrosion resistance
Zhifeng Zou Wenbin Xue Jiancheng Du Ming Hua Rongshan Wang Likui Weng
Key Laboratory for Beam Technology and Materials Modification of Ministry of Education, College of N Suzhou Nuclear Power Research Institute, Suzhou 215004, China
国际会议
北京
英文
756-761
2012-10-23（万方平台首次上网日期，不代表论文的发表时间）