镍基合金718在H2S/CO2环境中的腐蚀行为研究

运用腐蚀失重和电化学测量技术，研究了镍基合金718在模拟苛刻油田环境中的H₂S/CO₂腐蚀行为。结果表明，在模拟高温高压H₂S/CO₂腐蚀环境中，718合金腐蚀轻微，表现出良好的抗均匀腐蚀和局部腐蚀能力。电化学测试结果表明，在模拟CO₂腐蚀环境中，718合金的阳极极化曲线存在明显的钝化区，而在模拟H₂S/CO₂腐蚀条件下的阳极极化曲线呈现多次活化-钝化转变现象，表明腐蚀产物膜的稳定性降低；EIS表明阻抗谱均有明显的容抗弧特征，不含H₂S时材料显示单一的容抗弧，加入H₂S时低频显示扩散阻抗控制，饱和CO₂溶液中718合金具有相对较大的极化电阻。

Corrosion Behavior of Nickel-based Alloy 718 in Simulated H2S/CO2 Environments

In this paper, corrosion behavior of nickel-based alloy 718 in a H₂S/CO₂ containing solution, which simulated the harsh formation water of an oil field, was studied by means of mass loss method and electrochemical measurement techniques. The results show that in the simulated high temperature and high pressure H₂S/CO₂ corrosive environment, the 718 alloy is slightly corroded and exhibits good resistance to uniform corrosion and local corrosion. A passivation region appears clearly on the anodic polarization curve of 718 alloy in the CO₂-suturated solution, while there existed multiple activation-passivation transition phenomena on the anodic polarization curve in the H₂S/CO₂-saturated solution, it shows that the stability of the corrosion product film is reduced. EIS measurements indicate that the Nyquist plot of 718 alloy is composed of single capacitance loop in the solution without H₂S, when H₂S coexists with CO₂, the plot revealed the corrosion characteristics of diffuse control at low frequencies, and the 718 alloy in the solution filled with saturated CO₂ has a relatively large polarization resistance.