低浓度硼对锆合金缓蚀作用研究

Inhibition Effects of Low Concentration of Boron on Corrosion of Zirconium Alloy

采用动电位枀化和电化学阻抗谱法(EIS)研究了核电厂包壳材料锆合金在3种pH值相同的正常硼锂水质中的高温电化学腐蚀行为;采用高压釜腐蚀增重和微观分析等手段研究了锆合金在2种锂浓缩水质中的均匀腐蚀行为。高温电化学腐蚀试验表明:在3种pH值相同的正常硼锂水质中,随着硼浓度的增加,锆合金的钝化电流密度减少而交流阻抗值增大,硼对减缓锆合金的腐蚀有利。均匀腐蚀试验表明:相对于无硼的锂浓缩水质而言,加硼显著降低了锆合金的腐蚀增重量,减少了氧化膜厚度,幵使氧化膜更为致密,对提高锆合金的耐锂浓缩加速腐蚀有明显作用。

The high temperature electrochemical corrosion behavior of zirconium alloy was studied by potential dynamic polarization and electrochemical impedance spectrogram(EIS)under three normal boron-lithium water chemistry conditions with the same pH and the uniform corrosion behavior of zirconium alloy was investigated by weight gain and microanalysis under two lithium-concentrated water chemistry conditions.The high temperature electrochemical corrosion tests indicate that the increase of boron concentration can reduce the passive current density and increase the electrochemical impedance value of zirconium alloy under three normal boron-lithium water chemistry conditions despite of the same pH,consequently the boron is beneficial to corrosion inhibition of zirconium alloy.The uniform corrosion tests show that adding boron can obviously decrease the corrosion weight gain,oxide film thickness and compact the oxide films by contrast to the lithium-concentrated water chemistry condition without boron,thus the boron is beneficial to improve the corrosion resistance of zirconium alloy under lithium concentrated water chemistry conditions.