耐蚀合金材料点蚀及高温高压腐蚀性能研究

研究了镍基合金材料在高温高压腐蚀环境下的腐蚀性能以及在含氧化性离子溶液中的点蚀敏感性.采用了溶液浸泡法、电化学极化曲线方法进行试验,并结合扫描电镜以及能谱分析手段对两种镍基合金的腐蚀特性进行了研究.利用高温高压釜研究了在高温高压条件以及含H2S/CO2气体介质下材料的高温腐蚀性能以及试验温度的影响关系.依据相关标准在氯化铁溶液中进行了材料的点蚀敏感性研究.试验结果表明：G3合金的耐点蚀性能优于Incoloy 825,其点蚀临界温度高于50℃;两种镍基合金材料在FeCl3水溶液中的动电位极化曲线显示不同的腐蚀状态,Incoloy 825合金极化曲线中阳极曲线部分很平缓,无钝化区出现,极化度较低,G3阳极钝化区较明显,点蚀电位相对较高;高温高压腐蚀试验显示,随着温度升高,腐蚀程度加剧,腐蚀产物主要有NiS、FeS及CrO3等金属氧化物组成.

Study on Pitting Corrosion Characteristics and Corrosion Behavior of Ni-based Alloys

Aimed at the problems of the pitting corrosion and high temperature corrosion behavior of two Ni-based alloys,the polarization curve and immersion test were employed to study the electrochemistry corrosion behavior in FeCl3 solution and corrosion characteristics in high temperature and high pressure autoclave containing H2S/CO2.The results showed that the pitting-resistance of G3 was superior to Incoloy 825,and the critical pitting temperature was higher than 50 ℃.The polarization curve showed that there were different corrosion behavior of two types of alloy,anodic curve of G3 was passivation area,and there existed higher pitting potential.With the increasing of experimental temperatures,the corrosion increased.The main corrosion products were NiS,FeS and the oxides of Ni and Cr.