采用动电位极化、电化学阻抗、扫描电镜(SEM)、扫描Kelvin探针(SKP)和Raman光谱研究了300M和AerMet 100超高强度钢盐雾实验后试样的电化学行为. 结果表明, 300M钢在盐雾实验中生成的腐蚀产物为γ-FeOOH和Fe(OH)3; AerMet 100的腐蚀产物为 β-FeOOH, Fe3O4和γ-Fe2O3. Fe3O4和γ-Fe2O3较 γ-FeOOH致密, 更加有效阻碍了O2和Cl-的扩散, 对基体起到很好的保护作用. 随盐雾时间的延长, 2种钢的腐蚀电位均降低, 腐蚀电流密度均增大, 阳极溶解作用增强; 300M钢的腐蚀产物电阻随腐蚀产物的集聚而增大, 随脱落而减小; 带腐蚀产物的 AerMet 100的电化学过程受扩散作用控制, Warburg阻抗随盐雾进行而增大. 盐雾实验后2种超高强度钢的Kelvin电位值较未盐雾时高0.5-0.6 V, 且整个测试面的Kelvin电位值随盐雾时间的延长而逐渐不均匀. 300M的腐蚀产物保护作用较差, AerMet 100的耐蚀性和腐蚀产物的保护性能优于300M.
The electrochemical behaviors of ultra high strength steels, 300M and AerMet 100, with corrosion products which were formed during salt spray test were studied using potentiodynamic polarization curve, EIS, SEM, scan Kelvin probe (SKP) and Raman spectroscopy. The results show that the corrosion products on the steel 300M are γ-FeOOH and Fe(OH)3, and those on the steel AerMet 100 are β-FeOOH, Fe3O4 and γ-Fe2O3 after salt spray test. Because of the compact characterization, Fe3O4 and γ-Fe2O3 have a better protection property for substrate by hindering the permeation of O2 and Cl-. The corrosion potentials shift negatively and corrosion current densities become larger with increasing salt spray time, meaning a faster rate of anodic dissolution for these two steels. After salt spray test, the values of Kelvin potential for the two steels are 0.5-0.6 V positive than those before tests, and more uneven. For 300M, the corrosion resistance of rust layer becomes larger/smaller with the corrosion productions gathering/drapping on/from the samples. The electrochemical reaction for AerMet 100 is diffusion--controlled process and the value of Warburg impedence which expresses the diffusion--hindering effect becomes larger. The corrosion resistance and protection ability of corrosion products for steel AerMet 100 are better than those of steel 300M.
[1] Gra¸ca M L A, Hoo C Y, Silva O M M, Lourenco N J. Eng Fail Anal, 2009; 16: 182
[2] Ritchie R O, Horn R M. Metall Mater Trans, 1978; 9A: 331
[3] Garrison W M J, Moody N R. Metall Mater Trans, 1987; 18A: 1257
[4] Li J, Li Z, Yan M G. Mater Eng, 2007; (4): 61
(李杰, 李志, 颜鸣皋. 材料工程, 2007; (4): 61)
[5] Hao X L, Liu J H, Li S M, Yu M,Wang ZW. J Aeronaut Mater, 2010; 30(1): 67
(郝雪龙, 刘建华, 李松梅, 于美, 王宗武. 航空材料学报, 2010; 30(1): 67)
[6] Liu D X, Jin S, He J W. Spec Steel, 1997; 18(6): 20
(刘道新, 金 石, 何家文. 特殊钢, 1997; 18(6): 20)
[7] Youngblood J L, Raghavan M. Metall Trans, 1977; 8A: 1439
[8] Padmanabhan R, Wood W E. Mater Sci Eng, 1984; 66: 125
[9] Pound B G. Acta Mater, 1998; 46: 5733
[10] Figueroal D, Robinson M J. Corros Sci, 2010; 52: 1593
[11] Zhang H, Li X G, Du C W, Qi H B, Huang Y Z. J Raman Spectrosc, 2009; 409: 656
[12] Hao X C, Su P, Xiao K, Dong C F, Li X G. Corros Prot, 2009; 30: 297
(郝献超, 苏 鹏, 肖 葵, 董超芳, 李晓刚. 腐蚀与防护, 2009; 30: 297)
[13] Fu A Q, Tang X, Cheng Y F. Corros Sci, 2009; 51: 186
[14] Evans U R. Corros Sci, 1972; 12: 227
[15] Zhong J Y, Sun M, Liu D B, Li X G, Liu T Q. Int J Miner Metall Mater, 2010; 17: 282
[16] Ting X, Cheng Y F. Electrochim Acta, 2009; 54: 1499
[17] Dong C F, Sheng H, An Y H, Li X G, Xiao K, Cheng Y F. Prog Org Coat, 2010; 67: 269
[18] Sun M, Xiao K, Dong C F, Li X G. Acta Metall Sin (Engl Lett), 2010; 23: 301
[19] Zhou J L, Li X G, Du C W, Li Y L, Li T, Pan Y. Acta Metall Sin, 2010; 46: 251
(周建龙, 李晓刚, 杜翠薇, 李云玲, 李涛, 潘莹. 金属学报, 2010, 46: 251)
