摘要
采用恒电位C形环SCC试验方法,研究800合金在含0.3％SiO_2和0.3％Na_2S_2O_3的沸腾50％NaOH溶液中的SCC行为,并结合极化曲线测试及表面膜俄歇电子能谱(AES)分析结果进行了讨论。结果表明,在约-0.30V(SCE)以上的较高电位钝化区,800合金对碱性SCC非常敏感,而在约-0.45V(SCE)以下电位,SCC敏感性大大降低。这与较高电位下生成严重贫铬的Ni和Fe的氧化膜,而较低电位下生成由Cr、Fe、Ni的氧化物共同组成的表面膜密切相关。
The SCC behavior of Alloy 800 in boiling 50%NaOH solution containing 0.3% SO2 and 0.3%Na2S2O3 was studied using C-ring specimens at controlled potentials. A discussion was given based on the results of SCC tests, anodic polarization curves and AES analyses. Alloy 800 exhibited high susceptibility to caustic SCC in the passive region at potentials more noble than ca. -0.30V (SCE) and was much less susceptible to SCC at potentials more active than ca. -0.45V (SCE). The difference in SCC susceptibility was associated with the composition of surface films formed in different potential ranges. The surface film formed at higher potentials consisted of oxides of Ni in predomination with some Fe and little Cr, while that formed at lower potentials was composed of oxides of Cr, Ni and Fe. The latter showed much higher resistance to caustic SCC.
出处
《中国腐蚀与防护学报》
CAS
CSCD
1997年第3期181-187,共7页
Journal of Chinese Society For Corrosion and Protection
关键词
800合金
传热管
应力腐蚀
破裂
Alloy 800, Caustic SCC, C-ring, Polarization curves, AES
