苛刻工况条件下钛合金管材的腐蚀电化学特性研究

Study on Corrosion Electrochemical Properties of Titanium Alloy Tubes in Severe Environment

通过室内模拟腐蚀失重试验以及高温高压原位电化学测试分析,研究了TC4钛合金在苛刻腐蚀环境中的电化学特性。结果表明：在模拟含CO2和H2S地层水腐蚀环境中,TC4钛合金具有极其优越的抗均匀腐蚀及点蚀性。在180℃时均匀腐蚀速率仅为0.0008mm/a。TC4钛合金的阳极极化曲线均存在明显钝化区,钝化膜起到良好的保护作用,腐蚀速率仍保持在较低水平;极化电阻随温度的升高而减小,抗腐蚀性有所减弱。但在高达180℃时其钝化膜仍具有良好的热力学稳定性,表现出了较好的抗CO2和H2S腐蚀性;钛合金钝化膜的半导体类型为n型,具有阳离子选择性,可排斥Cl-等侵蚀性离子对钝化膜的侵蚀,有很强的耐蚀性。

The electrochemical properties of TC4 titanium were studied by room temperature simulation corrosion mass loss test and high temperature and high pressure in-situ electrochemistry analysis. The results show that TC4 has good resistance to uniform corrosion and pitting corrosion in lbrmation water corrosion environment containing C02 and H2S. The unitbrm corrosion rate is only 0.0008 mm/a at 180 ℃. The anodic polarization curves of TC4 titanium alloy has obvious passivation zone. The passivation coating plays a good protection effect. The corrosion rate is kept at a low level. The polarization resistance decreases with increasing temperature, and the corrosion resistance is weakened. But up to 180 ℃, the passive film still has good thermodynamic stability showing better resistance to CO2, and H2S corrosion; the semiconductor type of titanium alloy passivation film is n-type with cationic selectivity, which can exclude Cl^- and other corrosive ions from the erosion of the passivation film, and has strong corrosion resistance.