采用低温气体多元共渗技术在N80钢表面制备了碳、氮、氧、铬共渗层,采用SEM、EDS等分析了渗层形貌、厚度及共渗元素的分布;采用XRD测定了共渗层的相组成;在饱和CO2模拟油田介质中测试了共渗层的极化曲线与渗层的腐蚀速率.结果表明:渗层厚约70 μm,由靠近基体含有大量Cr-O相约40 μm厚的氧化物层、紧邻氧化物层含有ε、γ′相约15 μm厚的氮化物层及最外层的铁氧化物层组成;碳、氮、氧、铬共渗层自腐蚀电位比基体正移320 mV,在饱和CO2模拟油田介质中腐蚀速率仅为基体的1/3.

Using low temperature gas multi-component co-penetrated technique,C-N-O-Cr co-penetrated layer was obtained on the surface of N80 steel.The phase composition,morphology,thickness and the distribution of the co-penetrated elements of the co-penetrated layer were investigated by means of XRD,SEM and EDS.The polarization curve and the corrosion rate of the penetrated layer in the simulated saturated oilfield brine with carbon dioxide were tested.The results show that the thickness of the penetrated layer was about 70 μm.And the layer was composed of the 40 μm oxide layer with many Cr-O phase around the substrate,15 μm nitride layer with ε phase and γ′ phase near the oxide layer and the outmost iron oxide layer.To compare with the substrate,the corrosion potential of the C-N-O-Cr penetrated layer increased 320 mV in positive direction,the corrosion rate in the simulated saturated oilfield brine with carbon dioxide was only one-third of that of the substrate sample.