Cu,P,Cr和Ni对低碳钢耐蚀性的影响

Effect of Micro-alloying Elements on Corrosion Resistance of Low Carbon Steels

选择Cu-P-Cr-Ni钢、Cu-P-Cr钢和Q235碳钢,在0.01 mol/L的NaHSO3溶液中进行周期浸润、阻抗谱和极化曲线实验,研究了Cu-P-Cr-Ni系合金钢相比Q235碳钢在模拟工业大气(SO2)环境下的耐腐蚀性能;利用SEM,EPMA面扫描和XRD分析腐蚀锈层的形貌、组成及Cu,Cr和Ni的元素分布情况。结果表明:Cu-P-Cr-Ni系钢的腐蚀诱发敏感性最低,其次为Cu-P-Cr钢,腐蚀速率分别为Q235碳钢的59.5%和52.8%;锈层分为内、外两层,致密的内锈层明显发生Cu的颗粒状、Cr的团聚状富集,外锈层主要有Cr的富集,Ni富集不明显。Cu和Cr等的富集可形成致密的内锈层,提高低碳钢的耐蚀性。

Corrosion behavior of Cu, P, Cr and Ni alloyed low carbon steels and plain carbon steels was examined by means of cyclic immersion corrosion test, electrochemical impedance spectroscopy and polarization curve measurements with 1% （mass fraction） NaHSO3 solution. Corrosion resistance of Cu-P-Cr-Ni low carbon steels and Q235 carbon steel was also examined in SO2 atmosphere. Corrosion rust layers were analyses by SEM, EPMA and XRD. The results show that Cu-P- Cr-Ni steels exhibit weaker pitting susceptibility and lower pit propagation rate than carbon steel. The cyclic immersion corrosion rates were 59.5% and 52.8% of that of Q235 carbon steel for Cu-P- Cr-Ni and Cu-P-Cr steels respectively. Corrosion rust can be differentiated into inner layer and outer layer. Cu and Cr were concentrated in the inner layer and Cr enriched in the outer layer. The enrichment of Ni was not obvious. Thereby the corrosion resistance of low carbon steels was enhanced by the Cu and Cr-alloying.