含O2高温高压CO2环境中3Cr钢腐蚀产物膜特征  

Characteristics of Corrosion Scale of 3Cr Steel at High Temperature and Pressure in an O_2and CO_2Environment

作　　者：林学强[1] 柳伟[1] 张晶[1] 董帅[1] 张海龙[2] 李效波[2] 徐川川[1] 路民旭[1] 

机构地区：[1]北京科技大学新材料技术研究院,腐蚀与防护中心,北京100083 [2]中海油田服务股份有限公司,天津300450

出　　处：《物理化学学报》2013年第11期2405-2414,共10页Acta Physico-Chimica Sinica

摘　　要：采用高温高压反应釜分别开展3Cr钢在CO2和O2共存、单独CO2和单独O2三种气体条件下的腐蚀实验,利用X射线衍射仪(XRD)、扫描电子显微镜(SEM)、能量色散X射线能谱(EDS)和电化学方法研究了3Cr钢在高温高压含有O2的CO2环境中的腐蚀产物膜特征.结果表明,在含有O2的CO2的条件下,3Cr钢表面腐蚀产物膜疏松多孔,主要成分为FeCO3、Fe3O4和Fe2O3,腐蚀产物中未见明显Cr元素富集,3Cr钢表现出点蚀的腐蚀形态.3Cr钢在高温高压含O2的CO2腐蚀条件下内外膜层电阻(Rf1、Rf2)和电荷传递电阻Rt均比仅含有CO2腐蚀环境的低,双电层电容(Cdl)和内外膜层电容(Cf1、Cf2)均比仅含有CO2腐蚀环境的高.含有O2的CO2条件下,其保护性显著低于单一CO2条件下形成的腐蚀产物膜.提出了在含O2的CO2气体条件下,3Cr钢表面存在由多种物质组成的腐蚀产物,这导致腐蚀产物疏松多孔,不会形成单一CO2条件下存在的显著提高腐蚀产物膜保护性的Cr(OH)3层,从而促进了3Cr钢的析氢腐蚀和酸性介质中的吸氧腐蚀的机理.The corrosion behavior of 3Cr steel in atmospheres composed of only O2 or CO2 or a combination of O2 and CO2 was investigated using an autoclave. The characteristics of the corrosion scale of the 3Cr steel were investigated by X-ray diffraction （XRD）, scanning electron microscopy （SEM）, energy dispersive X-ray spectrometry （EDS）, and electrochemical methods. The corrosion scale developed in the combined O2 and CO2 atmosphere was composed of FeCO3, Fe2O3, and Fe3O4, and had a loose texture with a large number of pores. The surface and subsurface corrosion film resistance （Rf1, Rf2） and charge transfer resistance （R,） were all lower than those found in samples treated in only CO2 or O2 atmospheres. The double-layer capacitance （Cd,） and corrosion film capacitance （C11 C12） were higher for the sample treated in the combined 02 and CO2 atmosphere than for those treated in only CO2 or O2 atmospheres. The resistance to formation of a corrosion film on the 3Cr steel in the combined O2 and CO2 atmosphere was significantly lower than in the CO2 only atmosphere. The corrosion mechanism of 3Cr steel is proposed： In the O2 and CO2 environment the corrosion is proceed by the formation of several corrosion products causing a loose film to develop, The Cr（OH）3 layer which can greatly improve the protection of the corrosion film formed in a CO2 only corrosion environment is not found in the O2 and CO2 environment, thus promoted the corrosion process of hydrogen evolutional and oxidation corrosion in acid medium.

关 键 词：O2腐蚀 CO2腐蚀 3Cr钢 腐蚀速率 腐蚀形貌 

分 类 号：TG174.3[金属学及工艺—金属表面处理]