元素S对镍基合金G3在高温高压H2S/CO2气氛中腐蚀行为的影响

利用美国Cortest公司高温高压反应釜模拟H2S/CO2及元素S共存环境,在流动高矿化度饱和H2S/CO2介质中进行试验,然后利用SEM、EDS及XPS等表面分析技术,探讨元素S对镍基合金G3高温高压H2S/CO2腐蚀行为的影响。结果表明:在元素S含量为0、1及10 g/L时,镍基合金G3的平均腐蚀速率变化不大,钝化膜厚度约为11 nm,其结构呈双极性,外层以Cr、Ni的氢氧化物、氧化物为主,内层以Cr、Ni的氧化物为主;当元素S含量增大到100 g/L时,腐蚀速率急剧增大,钝化膜厚度也迅速增大到约90 nm,且结构转变为外层以Cr、Ni的硫化物为主,内层以Cr、Ni的氧化物为主;钝化膜结构的转变可能是导致镍基合金G3耐蚀性能降低的最主要原因。

Effect of element S on corrosion behavior of nickel-base alloy G3 in high temperature and high pressure environments containing H2S/CO2

The solution immersion environments containing H2S/CO2 and element S were simulated in a high temperature and high pressure autoclave.The effect of element S on the corrosion behavior of nickel-base alloy G3 was analyzed and discussed by the following technologies,such as SEM,EDS and XPS.The results show that the average corrosion rate of nickel-base G3 changes lightly and the thickness of passive film with bipolar structure is about 11 nm under the element S contents of 0,1 and 10 g/L.The out layer of passive film is mainly composed of oxides and hydroxides and the inner layer is mainly oxides.However,when the content of element S reaches 100 g/L,the average corrosion rate of nickel-base G3 increases rapidly,and the thickness of passive film also increases to about 90 nm.The out layer changes greatly and is mainly composed of Cr and Ni sulfide,the inner layer is still mainly Cr and Ni oxides.The transformation of passive film structure maybe is the main reason that results in the lower corrosion resistance of nickel-base G3.