摘要
通过高温高压腐蚀速率和应力腐蚀开裂(SCC)性能评价试验,辅以原位电化学测试分析,研究TC4钛合金石油管材在苛刻CO_2环境中的腐蚀行为和耐蚀机理。结果表明:TC4钛合金在高温高压CO_2腐蚀环境中具有极其优越的抗均匀腐蚀、局部腐蚀和SCC性能,在高达220℃的温度条件下均匀腐蚀速率仅为0.0012 mm/a。TC4钛合金在CO_2环境中的阳极极化曲线均有明显钝化区,腐蚀反应为阳极过程控制;随温度升高,TC4钛合金的自腐蚀电位降低,极化电阻减小,电化学腐蚀的热力学驱动力增大,而动力学阻滞性能减弱,腐蚀速率增大;但在高温CO_2腐蚀环境中,TC4钛合金的保护电位和点蚀电位较高,仍具有良好的钝化和再钝化能力,其在180℃时的极化电阻高达2328.2?·cm^2,具有良好的抗CO_2腐蚀性能。
The corrosion behavior and corrosion mechanism of TC4 titanium alloy OCTG in severe CO2 environment were studied with high temperature and high pressure and stres corrosion cracking （SCC） test, as well as electrochemical in-situ measurement techniques. The results show TC4 titanium alloy possesses the excellent resistance to uniform corrosion, local corrosion and SCC in high temperature and high pressure CO2 corrosion environment, and its uniform corrosion rate is only 0.0012 mm/a at the temperature up to 220 ℃. The anodie polarization curves of TC4 titanium alloy have the obvious passivation zone in CO2 environment, and the corrosion reaction is controlled by anodic process. With temperature increasing, the corrosion potential and polarization resistance of TC4 titanium alloy decrease, which indicate that the thermodynamic driving force of the electrochemical corrosion increases, while the dynamic resistance decreases; thus the corrosion rate of TC4 titanium alloy increases. However, the protective potential and pitting potential of TC4 titanium alloy are higher enough in high temperature CO2 corrosion environment, and the polarization resistance is up to 2328.2 Ω·cm2 at 180 ℃, which still give TC4 titanium alloy the good passivation and re-passivation ability and the superior resistance to CO2 corrosion at high temperature.
出处
《稀有金属材料与工程》
SCIE
EI
CAS
CSCD
北大核心
2018年第1期151-156,共6页
Rare Metal Materials and Engineering
基金
国家自然科学基金(51271146)
陕西省自然科学基础研究计划(2016JM5064)
陕西省石油专用管腐蚀与防护重点科技创新团队基金
