氨分缩器管板TA9合金层在氨环境中腐蚀特性研究  

Corrosion Characteristics of TA9 Alloy Layer on Ammonia Condense Separator Tube Sheet under Ammonia Environment

作　　者：刘行宇 李宏燕[1] 袁天孝 张东峰 LIU Xingyu;LI Hongyan;YUAN Tianxiao;ZHANG Dongfeng(School of Mechanical Engineering,Ningxia University,Yinchuan 750021,China)

机构地区：[1]宁夏大学机械工程学院,宁夏银川750021

出　　处：《材料保护》2023年第8期184-190,共7页Materials Protection

基　　金：宁夏省自然科学基金项目(2021AAC03082)资助。

摘　　要：针对煤焦化硫铵生产中氨分缩器换热管板的腐蚀破坏现象,通过全浸泡试验及电化学试验探究了管板TA9合金层的耐蚀特性。利用扫描电镜(SEM)、X射线能谱仪(EDS)对TA9合金在不同温度条件下,分别含有S^(2-)、Cl^(-)、F^(-)3种阴离子及3种阴离子混合的氨水溶液中全浸试验后的腐蚀产物进行了分析;利用电化学工作站对TA9合金的腐蚀速率及表面钝化膜的耐蚀特性进行了探究。结果表明:随温度升高,TA9合金的全面腐蚀和点蚀均逐渐增强,同一温度下不同阴离子作用时腐蚀宏观形貌无显著差异,其腐蚀产物均为钛的氧化物。TA9合金的腐蚀速率受温度影响较大,在3种阴离子混合的氨水溶液中,当温度由20℃提高至90℃时,腐蚀速率由1.05997μm/a提高至10.61974μm/a,腐蚀速率增加了近10倍;当温度上升至50℃后,钝化膜对材料的保护性能降低;相同温度下F^(-)单独存在时电极表面的钝化膜电阻R变化显著,氧化还原反应最为剧烈,导致电极表面钝化膜溶解速率最快,TA9合金腐蚀速率最高。According to the corrosion damage of heat exchange tube plate of ammonia condense separator in coking ammonium sulfide production, the corrosion resistance characteristics of the surface passivation film of tube sheet TA9 alloy were studied by total immersion test and electrochemical analysis. Using scanning electron microscope(SEM) and X-ray energy dispersive spectrometer(EDS), the corrosion products of samples after total immersion test were analyzed under different temperature conditions in ammonia solution containing S^(2-), Cl^(-), F^(-) anions or a mixture of these anions, respectively. The corrosion rate of TA9 alloy and the corrosion resistance characteristics of the surface passivation film were investigated using an electrochemical workstation. Results showed that the general corrosion and pitting corrosion of TA9 alloy gradually increased with the increase of temperature, and there was no obvious difference in the macroscopic morphology of corrosion under the action of different anions at same temperature and the corrosion products were titanium oxides. The corrosion rate of the TA9 alloy was greatly affected by temperature. In an ammonia aqueous solution mixed with three anions, when the temperature was increased from 20 ℃ to 90 ℃, the corrosion rate increased from 1.059 97 μm/a to 10.619 74 μm/a, so the corrosion rate increased nearly 10 times. As the temperature rose to 50 ℃, the protective performance of the passivation film to the material decreased. At the same temperature, when fluoride ions existed alone, the resistance R of the passive film on the electrode surface changed significantly, and the redox reaction on the electrode surface was the most violent, resulting in the fastest dissolution rate of the passivation film on the electrode surface and the highest corrosion rate of TA9 alloy.

关 键 词：TA9合金 氨分缩器管板 离子类型 电化学分析 腐蚀速率 

分 类 号：TG172[金属学及工艺—金属表面处理]