深海环境下静水压力与浸泡时间对304不锈钢电化学行为影响

Effects of hydrostatic pressure and soaking time on electrochemical behavior of 304 stainless steel in deep sea environment

以304不锈钢为研究对象,使用自主搭建的低温高压釜模拟深海高静水压力环境,研究不同静水压力下浸泡时间对304不锈钢腐蚀行为的影响。利用原位电化学阻抗谱与动电位极化曲线评价304不锈钢的自腐蚀电位、自腐蚀电流密度、电化学阻抗谱及其拟合电路。实验表明,随着静水压力的增加,304不锈钢浸泡24 h与120 h的耐腐蚀性能都下降,其电荷转移电阻从0.1 MPa的3.614×10^(6)Ω·cm^(2)与2.482×10^(6)Ω·cm^(2)下降至10 MPa的7.592×10^(4)Ω·cm^(2)与7.073×10^(4)Ω·cm^(2)。在相同的静水压力,随着浸泡时间的增加,304不锈钢的耐腐蚀性能降低,由10 MPa静水压力下浸泡24 h延长到120 h后,腐蚀电流密度从1.197×10^(-7) A∙cm^(-2)上升至4.48×10^(-7) A∙cm^(-2)。

A self-built low-temperature autoclave was used to simulate the high hydrostatic pressure deep sea environment,and the effects of soaking time on the corrosion behavior of a 304 stainless steel were studied un-der different hydrostatic pressures.The self-corrosion potential,self-corrosion current density,and electro-chemical impedance spectroscopy and its fitting circuit were evaluated for the steel by in-situ electrochemical impedance spectroscopy and potentiodynamic polarization curves.The results show that:the corrosion resis-tance of the steel soaked for 24 h and 120 h both decreased with the increase in hydrostatic pressure,and the charge transfer resistance decreased from 3.614×10^(6)Ω·cm^(2) and 2.482×10^(6)Ω·cm^(2) under 0.1 MPa to 7.592×10^(4)Ω·cm^(2) and 7.073×10^(4)Ω·cm^(2) under 10 MPa.Under the same hydrostatic pressure,the corrosion resistance of the steel also decreased with the increase in soaking time.The corrosion current density increased from 1.197×10^(-7) A∙cm^(-2) to 4.48×10^(-7) A∙cm^(-2) when the soaking time increased from 24 h to 120 h under 10 MPa hy-drostatic pressure.