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

该研究的目的是温度的影响相关联，H ₂ S和氯^-浓度对被动限制和局部腐蚀的在UNS S31603不锈钢通过在半导体行为评估的变化表现出发病由无源层。该研究是通过使用直流和交流电化学方法相结合的实验来完成的，以研究由不锈钢形成的钝化层，该钝化层与2.8 MPa（400 psi）的气相平衡，并含有高达60％mol的H ₂ S （平衡CO ₂）的温度范围是25°C至150°C。获得的结果表明，在UNS S31603不锈钢上形成的钝化层稳定性的降低与电子给体载流子密度的增加是一致的。这被观察为的温度的作用的结果和Cl的浓度^-和H ₂ S.在这种情况下，氯^-在盐水中含量被发现施加比H较大的效果₂在恒定的温度S活性。