非金属夹杂物对耐候钢耐大气腐蚀性能的影响

The Effects of Non-metallic Inclusions on the Weatherability of Weathering Steel

采用干湿交替周期浸润腐蚀实验和场发射扫描电镜研究了非金属夹杂物对Q450NQR1耐候钢在工业性大气环境中耐候性的影响。结果表明,夹杂物变性处理明显提高了耐候钢前期的耐腐蚀性能,但对稳定性锈层形成之后的耐腐蚀性能基本没有影响;经过稀土处理后的非金属夹杂物主要为稀土氧化物和硫化物与Al2O3的复合夹杂,添加Si-Ca线变性后的非金属夹杂物主要为Ca的氧化物和硫化物与Al2O3的复合夹杂,这些夹杂物在0.01 mol·L-1的Na HSO3介质中均表现为阳极性夹杂,在腐蚀微电池中作为阳极优先溶解,钢基体则作为阴极被保护起来,腐蚀速度减缓。

The wet / dry cyclic immersion corrosion test and filed emission scanning electron microscopy（ FE- SEM） were employed to investigate the effects of non metallic inclusions on the weatherability of weathering steel. The result showed that either RE- modification or Ca- modification on the inclusion could increase the initial corrosion resistance of Q450NQR1 remarkably,while the impact on the later corrosion period after the formation of the compact rust turned out to be small. After RE- modified,the inclusions were mainly compounds of RE oxides,RE sulfides and Al2O3,when Ca- modified,the inclusions were compounds of Ca oxides,Ca sulfides and Al2O3. The inclusions became anodic after inclusion modification and were eroded preferentially as anode in 0. 01 mol / L Na HSO3 during the corrosion reactions which protected the steel matrix from corrosion.