(湖南大學 材料科學與工程學院，長沙 410082)
摘 要: 采用電化學方法研究鋯合金Zr-4在添加不同Cu2+濃度的0.5 mol/L NaCl溶液或0.5 mol/L Na2SO4中的腐蝕行為，探討不同濃度Cu2+對Zr-4合金腐蝕性能的影響，同時，在10 g/L Na2SiO3·9H2O+10 g/L Na4P2O7·10H2O混合溶液中對Zr-4合金進行等離子電解氧化處理，并用極化曲線技術研究膜層的防護能力。結果表明：Cu2+能使Zr-4合金自腐蝕電位正移，降低極化曲線上鈍化區(qū)的寬度，使得合金的抗孔蝕能力降低，腐蝕電流密度增加；在硫酸鈉溶液中，Cu2+的添加沒有使合金產(chǎn)生明顯的孔蝕，這表明Zr-4合金的抗孔蝕能力下降是Cu2+和Cl−共同作用的結果；等離子電解氧化處理能夠大幅度提高Zr-4合金的抗孔蝕能力。
關鍵字: Zr-4合金；Cu2+；孔蝕；等離子電解氧化
（College of Materials Science and Engineering, Hunan University, Changsha 410082, China）
Abstract:The corrosion behavior of zicaloy-4 alloy in 0.5 mol/L NaCl+CuCl2 solution and 0.5 mol/L Na2SO4+CuSO4 solution was studied by electrochemical methods, and the effect of the concentration of Cu2+ on the corrosion behavior of zicaloy-4 alloy was discussed, meanwhile, plasma electrolytic oxidation(PEO) was carried out on the zircaloy-4 alloy in the electrolyte of 10 g/L Na2SiO3·9H2O+10 g/L Na4P2O7·10H2O, and the protection ability of the PEO coatings was evaluated by potentiodynamic polarization curves. The results show that that Cu2+ can shift the corrosion potential of the zircaloy-4 alloy toward the positive direction and narrows the scope of the passive region on the polarization curves, as a result, the resistance of the alloy to pitting corrosion decreases and the corrosion current density increases. In the solution of Na2SO4, the addition of Cu2+ does not result in obvious pitting corrosion of the alloy, manifesting that the decrease of the pitting resistance of the zircaloy-4 is the synergetic effect of Cu2+ and Cl−. PEO treatment can greatly enhance the pitting resistance of the zircaloy-4 alloy.
Key words: zircaloy-4 alloy; Cu2+; pitting; plasma electrolytic oxidation
