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通过中心复合设计试验法设计试验,结合动电位极化曲线和电化学阻抗谱的测量以及氧化膜形貌观察和成分测量,研究了温度(30~350℃)、Cl~-质量浓度(10~1000μg·L-1)和溶解氧质量浓度(0~200μg·L-1)3种因素对压水堆一回路主管道316L不锈钢电化学腐蚀性能的影响.结果表明:温度是影响316L不锈钢电化学腐蚀性能最显著的因素,温度越高,腐蚀电流密度越大,点蚀电位越低;Cl~-浓度和溶解氧浓度对316L不锈钢电化学腐蚀性能的影响与温度密切相关,温度较低时(T<150℃),Cl~-浓度和溶解氧浓度均对316L腐蚀电流密度几乎无影响,但点蚀电位却随Cl~-浓度增加和溶解氧浓度的降低而降低;温度较高时,分别为T>130℃和T>150℃,Cl~-浓度和溶解氧浓度均对316L点蚀电位几乎无影响,但腐蚀电流密度却随Cl~-和溶解氧的浓度增加而显著增加,腐蚀加剧.电化学阻抗谱的测量和氧化膜形貌的观察也进一步验证了上述试验结果.
Through the design experiment of composite design test in the center, the effects of temperature (30 ~ 350 ℃), Cl ~ - concentration (10 ~ 1000μg · L-1) and dissolved oxygen concentration (0 ~ 200μg · L-1) on the electrochemical corrosion of 316L stainless steel in the primary circuit of PWR were investigated.The results showed that the temperature affected the electrochemical performance of 316L stainless steel The higher the temperature, the higher the corrosion current density, the lower the pitting potential. The effect of Cl ~ - and DO concentration on the electrochemical corrosion of 316L stainless steel is closely related to the temperature. When the temperature is low T <150 ℃). Both Cl ~ - and DO concentration had little effect on the corrosion current density of 316L, but the pitting potential decreased with the increase of Cl ~ - concentration and dissolved oxygen concentration. When the temperature was high, At T> 130 ℃ and T> 150 ℃, both Cl ~ - and dissolved oxygen concentration had little effect on the pitting potential of 316L, but the corrosion current density increased significantly with the increase of Cl ~ - and dissolved oxygen concentration, which aggravated the corrosion The measurement of electrochemical impedance spectroscopy and the observation of the morphology of the oxide film are also advanced To confirm the above results.