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采用改进的D-S双电解池与慢应变速率拉伸实验机相结合,研究了阴极保护和应力耦合作用下X80钢在3.5%Na Cl+1 g/L Na2S溶液中的氢渗透行为。通过变电位氢渗透实验,分析极化电位对氢渗透行为的影响并得到析氢敏感电位。进行不同应力水平下的恒电位极化氢渗透实验,采用Laplace方程分析氢渗透曲线,计算相关的氢渗透参数。结果表明,在各个应力水平下,随阴极极化电位负移,稳态渗氢电流密度增大,析氢敏感电位负于-1000 m V(vs SCE)。在弹性应变时,氢陷阱密度变小,氢扩散系数增大;进入塑性变形阶段后由于位错产生,氢陷阱密度逐渐升高,氢扩散系数降低;吸附氢浓度与扩散系数呈现相反的变化规律。
Hydrogen permeation behavior of X80 steel in 3.5% NaCl + 1 g / L Na2S solution under cathodic protection and stress coupling was investigated using a modified D-S dual cell coupled with a slow strain rate tensile testing machine. Hydrogen permeation experiments were carried out to study the effect of polarization potential on hydrogen permeation and hydrogen evolution potential. Under different stress levels, potentiostatic hydrogen permeation experiments were carried out. The Laplace equation was used to analyze the hydrogen permeation curves, and the relevant hydrogen permeation parameters were calculated. The results show that at each stress level, the steady-state hydrogen permeation current density increases with negative cathodic polarization potential, and the hydrogen evolution sensitive potential is negative to -1000 mV (vs SCE). At elastic deformation, the hydrogen trap density becomes smaller and the hydrogen diffusion coefficient increases. Due to dislocation generation, the hydrogen trap density gradually increases and the hydrogen diffusion coefficient decreases as the plastic deformation stage enters. The hydrogen adsorption concentration and the diffusion coefficient exhibit the opposite variation .