利用自主组建的电化学测试装置,通过极化曲线和电化学阻抗谱测试,研究了四种不锈钢(编号为S1、S2、S3和S4)以及钛材(编号为S5)在新型热泵工作介质(甲酸钾溶液)中的电化学行为。结果表明:五种材料在80%(质量分数)甲酸钾溶液中的自腐蚀电流密度均随温度的升高而增大,S5钛材的腐蚀电流密度最大,S1不锈钢最小;S2、S3、S4三种不锈钢在温度低于125℃时表现出良好的耐蚀性,当温度较高时,其自腐蚀电流密度急速增大;五种材料的自腐蚀电流密度按从大到小的顺序依次为S5≈S4、S3、S2、S1(温度低于100℃),S5、S4、S3、S2、S1(温度高于100℃);S5的电荷传递电阻R_ct最大,S4、S3、S2的次之,S1的最小。

The electrochemical behaviors of four stainless steels (S1, S2, S3 and S4) and titanium material (S5) in a new heat pump medium (potassium formate solution) were studied by tests of polarization curves and electrochemical impedance spectroscopy. The results showed that the self-corrosion current density of five materials in 80% (mass fraction) potassium formate solution increased with the rise of temperature, the corrosion current density of S5 titanium material was the highest, and that of S1 stainless steel was the lowest. S2, S3 and S4 stainless steels exhibited good corrosion resistance when the temperature was below 125 ℃, and their self-corrosion current density increased rapidly when the temperature was relatively high. The self-corrosion current density rank of the five materials was S5≈S4,S3,S2,S1 when temperature below 100 ℃, S5, S4,S3,S2,S1 when temperature above 100 ℃. The charge transfer resistance R_ct of S5 was the largest, followed by that of S4, S3 and S2, and that of S1 was the smallest.