硫酸亚铁成膜失效的镍白铜冷凝管腐蚀机理分析

运用力学性能测试、扫描电镜观察、微区能谱成分分析和x射线衍射物相分析等手段对硫酸亚铁成膜的镍白铜冷凝管内壁腐蚀特性进行观察和分析.结果表明:镍白铜冷凝管服役前的组织和性能符合国家标准GB/T8890-1998的要求;硫酸亚铁成膜后的新管使用1年半后,管内壁有较厚的不均匀疏松沉积层,去除沉积层后,白铜管内壁有明显腐蚀现象,并且是明显点蚀坑和少量鼓包状腐蚀产物.由于点蚀坑内腐蚀产物中的CuS和CuCl2的含量较高,说明循环冷却水中硫离子(S2-)和氯离子(Cl-)参与了白铜管的腐蚀过程.

The Corrosion Mechanism of Failure of Copper - nickel Condenser Tubes Coated by Ferrisulphas

The corrosion mechanism of failure of copper-nickel condenser tubes coated by Ferrisulphas has been investigated by mechanical properties test,SEM observation, energy spectrum and XRD analysis.The results showed that the structure and property of copper-nickel condenser tubes before application were according to that of the GB /T8890-1998 standard.There were uneven loosen deposition adhering on the inner wall of the copper-nickel condenser tubes coated by Ferrisulphas after 1.5 year in application.The pitting corrosion hole and a little vesicle-shaped corrosion products appeared after the uneven loosen deposition removing.CuS and CuCl_(2)which were found in the pitting corrosion holes showed that the Cl~(1-) and S~(2-) of the water in the powder plant participated in the corrosion process of the copper-nickel condenser tubes.