铬酸盐对2024铝合金在NaCl溶液中缓蚀机制的影响  

Study on the Inhibition Effect of Chromate on Stress Corrosion of 2024 Aluminum Alloy in NaCl Solution

作　　者：刘畅达[1,2] 吴明 赵志浩[1] 王旭 杨玉洁[1] 

机构地区：[1]辽宁石油化工大学石油天然气工程学院,辽宁抚顺113001 [2]辽宁石油化工大学机械工程学院,辽宁抚顺113001

出　　处：《有色金属工程》2018年第1期61-65,88,共6页Nonferrous Metals Engineering

基　　金：国家自然科学基金(51574147)

摘　　要：采用慢应变速率试验(SSRT)和电化学测试技术系统研究了一定条件下2024铝合金在空气、NaCl溶液以及NaCl与Na_2CrO_4混合溶液中的腐蚀机制。结果表明,向NaCl溶液中添加CrO_4^(2-)后,2024铝合金表面上可形成能修补合金表面保护性氧化层的Cr(OH)_3,抑制阳极反应的进行,降低应力腐蚀敏感性,对合金起到缓蚀作用,这与慢应变速率1.0×10^(-6)s^(-1)下拉伸试验中2024铝合金力学性能提高5%相吻合。铬酸盐可以使2024铝合金在NaCl溶液中的断口横向裂纹减少,应力腐蚀敏感性因子降低31.6%。The slow strain rate tests （SSRT）, potentiodynamic polarization, electrochemical impedance spectroscopy and scanning electron microscopy （SEM） testing technology were used to research stress corrosion cracking （SCC） of 2024 Aluminum Alloy in air, NaC1 solution, NaC1 and NazCrO4 mixed solution respectively. The results showed that the Cr（OH）3 repairing protective oxide layer on the surface of 2024 aluminum alloy was formed by adding Na2 CrO4 to NaC1 solution, resulting in that anode reaction was restrained and the stress corrosion sensitivity was reduced. This result was consistent with 5% increase of the mechanical properties of 2024 aluminum alloy in the tensile test at a slow strain rate of 1.0 × 10-6 s-1. Na2CrO4 can reduce the transverse cracks of 2024 aluminum alloy in NaCl solution and reduce the stress corrosion susceptibility decreased by 31.6%.

关 键 词：2024铝合金 铬酸盐 慢应变拉伸试验 极化曲线 交流阻抗谱 

分 类 号：TG172.5[金属学及工艺—金属表面处理] TG174[金属学及工艺—金属学]