硅酸盐钝化对化工管道用钢耐蚀性能的影响

Effect of Silicate Passivation on Corrosion Resistance of Chemical Pipe-line Steel

为解决化工管道用钢耐蚀性差的问题,采用表面热浸镀锌和钝化处理的方法在化工管道用钢表面进行了保护层制备,研究了硅酸钠溶液中SiO_(2)/Na_(2)O摩尔比对保护层耐蚀性能的影响,并分析了硅酸盐转化膜的自愈性机理。结果表明,在镀锌试样表面进行硅酸钠溶液钝化处理可以提升材料的耐蚀性能,且随着钝化液中SiO_(2)/Na_(2)O摩尔比增加,钝化试样的耐蚀性能先增强后减弱,SiO_(2)/Na_(2)O摩尔比为3.5的钝化试样具有最佳的耐蚀性能,这主要与钝化处理后钝化膜中的Si发生迁移沉积,使得膜层具有一定自愈性而增强了耐蚀性能有关。

In order to solve the problem of poor corrosion resistance of chemical pipeline steel,a protective layer was prepared on the surface of chemical pipeline steel by surface hot-dip galvanizing and passivation.The effect of SiO_(2)/Na_(2)O molar ratio in sodium silicate solution on the corrosion resistance of the protective layer was studied,and the self-healing mechanism of silicate conversion film was analyzed.The results show that the passivation treatment with sodium silicate solution on the surface of galvanized sample can improve the corrosion resistance of the material,and with the increase of SiO_(2)/Na_(2)O molar ratio in the passivation solution,the corrosion resistance of passivated sample first increases and then decreases.The passivation sample with SiO_(2)/Na_(2)O molar ratio of 3.5 has the best corrosion resistance,which is mainly related to the migration and deposition of Si in the passivation film after passivation treatment.It makes the film have certain self-healing and enhances the corrosion resistance.