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本文系用模拟闭塞电池来研究1 Cr_(18)Ni_9Ti 奥氏体不锈钢在 C1~-+NO_3~-或 NO_2~-溶液中闭塞区内化学和电化学状态的变化。当 NO_3~-达到一定浓度时,闭塞区内 pH 下降比在单纯 C1~-溶液中缓慢,并且趋于一极限值(pH=2)后,即不再下降。裂尖溶液内 C1~-与 NO_3~-克当量比例和外部主溶液接近,但裂尖溶液浓缩数倍。当1法拉第电量通过闭塞区时,大约有0.5—0.7克当量的 C1~-+NO_3~-迁入闭塞区。裂尖内 NO_2~-的迁入量很微小。溶液中加入不同浓度 NO_3~-或 NO_2~-后,使破裂电位变为更正,表明NO_3~-和 NO_2~-有缓蚀作用。
In this paper, the simulated and occluded cells were used to study the changes of chemical and electrochemical states in the occluded area of 1 Cr 18 Ni 9 Ti austenitic stainless steel in C1 ~ + NO_3 ~ - or NO_2 ~ - solution. When NO_3 ~ reaches a certain concentration, the decrease of pH in the occluded area is slower than that in the pure C1 ~ - solution, and it will not decrease after reaching a limit value (pH = 2). In the crack tip solution, the ratio of C1 ~ - to NO_3 ~ - g is close to that of the external main solution, but the tip solution is concentrated several times. When a Faraday charge passes through the occlusion zone, about 0.5-0.7 gram equivalent of C1 ~ - + NO_3 ~ moves into the occlusion zone. In the crack tip NO_2 ~ - the influx is very small. After adding different concentration of NO_3 ~ - or NO_2 ~ - into the solution, the rupture potential becomes more positive, indicating that NO_3 ~ - and NO_2 ~ - have a corrosion inhibition effect.