QPQ技术与抗硫化氢腐蚀

QPQ technology and corrosion resistance in H_2S environment

通过抗硫化氢恒负荷拉伸试验,分析探讨了QPQ处理试样在饱和硫化氢溶液中的腐蚀机理。在饱和硫化氢溶液环境中,经QPQ处理试样的化合物层本身并不容易受到侵蚀,但由于硫化氢离解形成的氢离子和硫离子通过化合物层的缺陷如疏松或破损处,进入到化合物层与扩散层界面,使扩散层发生腐蚀,腐蚀产物体积膨胀产生应力迫使化合物层脱落和破坏。由于氢原子在化合物层中的扩散系数极低,因此在化合物层没有脱落时,QPQ处理后的材料基体中氢原子的浓度极低,从而提高了QPQ处理试样的抗硫化氢腐蚀性能。

The corrosion mechanism of QPQ treated specimens in H2S environment was analyzed and discussed through constant stress tensile test in H2S saturated solution.The results show that in H2S environment,the compound layer of QPQ treated sample is not easily eroded,but sometimes the hydrogen and sulphur ions from ionization of H2S enter into interface of compound layer and diffusion layer through defects as pores and breakages result in corrosion of diffusion layer,and the compound layer could break away due to the expansion of the corrosion product in interface.The diffusion coefficient of hydrogen atom in the compound layer is very low,so the hydrogen atom concentration in substrate is utmost low before the compound layer breaking and the corrosion resistance of QPQ treated samples in H2S environment can be improved.