ABSTRACT

The objective of the study is to correlate the effects of temperature, H₂S and Cl⁻ concentration on the passivity limits and the onset of localised corrosion in UNS S31603 stainless steel by evaluating the changes in the semiconducting behaviour exhibited by the passive layer. The study is accomplished experimentally by using a combination of direct and alternate current electrochemical methods to study the passive layer formed by the stainless steel, in equilibrium with a gas phase at 2.8 MPa (400 psi) containing up to 60% mol of H₂S (bal. CO₂) at temperatures from 25°C and up to 150°C. The results obtained indicate that the decrease of the passive layer stability formed on the UNS S31603 stainless steel is consistent with the increase in the electron donor carrier density. This is observed as a consequence of the effect of temperature and the concentration of Cl⁻ and H₂S. In this context, the Cl⁻ content in the brine was found to exert a larger effect than the H₂S activity at constant temperature.

摘要

该研究的目的是通过评估钝化层表现出的半导体行为的变化，将温度、H ₂ S 和 Cl ^-浓度对 UNS S31603 不锈钢的钝化极限和局部腐蚀开始的影响联系起来。该研究是通过使用直流和交流电化学方法的组合以实验方式完成的，以研究由不锈钢形成的钝化层，在 2.8 MPa (400 psi) 的气相中达到平衡，其中包含高达 60% mol 的 H ₂ S （平衡。CO ₂) 在 25°C 至 150°C 的温度下。所得结果表明，UNS S31603不锈钢上形成的钝化层稳定性的降低与电子施主载流子密度的增加是一致的。这是由于温度和 Cl ^-和 H ₂ S浓度的影响而观察到的。在这种情况下，发现盐水中的 Cl ^-含量比恒温下的 H ₂ S 活性产生更大的影响。