<正> 一、前言 氯离子是导致奥氏体不锈钢发生应力腐蚀破裂和孔蚀的特性离子。它从主体溶液迁入闭塞区已被许多作者的实验所证实。我们以前的工作证明Cl~-的迁入量与通过闭塞区的电量成直线关系,Cl~-增浓是促进闭塞区合金溶解的因素之一。I~-和Cl~-同属卤族离子,但据报道将I~-加入含Cl~-的体系对奥氏体不锈钢的应力腐蚀破裂具有抑制作用。显然探明特性离子(如Cl~-、I~-等)的作用有益于认识局部腐蚀的机理。本工作研究I~-的迁移规律以及对闭塞电池腐蚀的影响。 二、实验方法 1.闭塞电池不同阶段的溶液成份测定——模拟闭塞电池实验 采用文献[3]所用的方法,测量0.5mol/L NaCl溶液中加入0～0.3mol/L NaI后304不锈钢模拟裂缝不同阶段的溶液成份,进而了解I~-对缝内化学和电化学状态的影响。在“闭塞电
Simulated occluded cell(0C) was used to study the chemical and electrochemical changes within stress corrosion cracks for the system sensitized AISI304 steel/Cl~- with addition of different concentrations of I~-. The respective number of equivalents of migrated I~- as well as Cl~- was proportional to the quantity of electricity passing through the occluded cell. The ratio of migration rate of Cl~-/I~- was the same as that of the concentrations of those ions in bulk solution. The pH value inside occluded cell was independent of I~- migration, but the occcluded potential moved more positively than that without I~-. It was shown by potentiostatie weight loss method using simulated occluded solutions with different I~- concentrations that the migation of I~- from outside inhibited the occluded cell corrosion. The inhibition efficiency of 0C was more than 98％ when the concentration of I~- in bulk solution was only 0.01mol/L. So the iodide was an effective inhibitor of stress corrosion cracking for austenitic stainless steel in chloride solutions.
参考文献
| [1] | |
| [2] | |
| [3] | |
| [4] | |
| [5] | |
| [6] | |
| [7] | |
| [8] |
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