Cl~-对690合金在高温高压水中腐蚀行为的影响

采用扫描电子显微镜和X射线衍射仪研究了Cl-对690合金在高温高压水中腐蚀行为的影响。研究表明:690合金内外表面状态对其腐蚀形貌有显著影响,Cl-使得表面形成的钝化膜不均匀,出现较多的点蚀坑。溶液中的Cl-能够影响腐蚀产物膜的结构。当溶液中不含有Cl-时,腐蚀产物膜为双层结构,外层腐蚀产物为颗粒状;当溶液中含有Cl-时,腐蚀产物膜具有单层结构。XRD结果表明:两种环境中的钝化膜产物主要由Cr2O3、NiFe2O4、NiO等氧化物组成,但含Cl-条件下的氧化物较少。

Effect of Cl~- on corrosion behavior of alloy 690 in high temperature and high pressure water solution

The effect of Cl- on the corrosion behaviors of alloy 690 in high temperature and high pressure solution was investigated by SEM and XRD.The results show that the conditions of inside and outside surface have apparent effect on the corrosion morphology of alloy 690.The surface of passive film formed in solution with Cl- is uneven,and a lot of pits can be found.The Cl- of electrolyte has great effect on the structure of corrosion product.The corrosion product film formed in solution without Cl- has the double layer structure.The corrosion scale formed in the Cl--containing solution has a monolayer.The outer sub-film is composed of grainy crystal.The XRD results show that the passive film in the two environments mainly consists of Cr2O3,NiFe2O4,NiO and other oxides,but there is fewer oxides in the film formed in solution with Cl-.