将690合金样品在高压釜内进行4400 h含高温高压水腐蚀试验,采用扫描电子显微镜(SEM)、X射线衍射分析(XRD)、俄歇电子能谱(AES)和拉曼光谱(Raman)等研究690合金在含Pb高温高压水中形成的腐蚀产物膜,研究690合金在含Pb溶液中腐蚀产物膜的生长规模。结果表明:690合金在晶界处腐蚀较快,腐蚀形貌呈晶格网状;腐蚀产物膜中含有Pb呈外层富镍内层富铬的双层结构;腐蚀产物膜主要由Cr、NiFe、NiO等氧化物和Ni相组成;Pb掺杂于腐蚀产物膜,降低了腐蚀产物膜的保护性,增加了690合金的腐蚀速度。

Alloy 690 were put in autoclave to carry out corrosion test in high temperature and high pressure water containing Pb for 4400 h to study the corrosion film growth rule of alloy 690 in the solution containing Pb. The corrosion production film of alloy 690 in high temperature and high pressure water containing Pb was investigated by SEM, XRD, AES and Raman technique. The results show that the corrosion morphology is grain grid for the high corrosion rate of grain boundaries. The corrosion production film is the double layer, the outer layer is rich in Ni and the inner layer is rich in Cr. The corrosion production film is consisted of Cr 2 O 3 , NiFe 2 O 4 , NiO and other oxides. The new phase of Ni 2 Cr is found in the passive film formed in Pb-containing solution. Pb in the surface corrosion product leads to the decrease of protectiveness of the passive film and increase of stress corrosion sensitivity.

目的研究西南地区某输油管道外腐蚀行为。方法现场检测,对土壤理化性质及腐蚀产物成分进行室内分析。结果开挖点A的土壤呈弱碱性,土壤腐蚀性弱,管道发生轻微均匀腐蚀,腐蚀产物主要为FeO(OH),Fe(OH)3和Fe3O4等铁的氧化物,对应的阴极反应为吸氧反应;开挖点B的土壤酸性强,硫酸根离子浓度高,土壤腐蚀性强,管道发生严重坑蚀,腐蚀产物主要成分为FeSO4·7H2O及少量碱式硫酸铁,对应的阴极反应以析氢反应为主。结论开挖点土壤的理化性质差异,导致管道的腐蚀形态、腐蚀产物和腐蚀机理显著不同。

Objective To investigate the external corrosion for two excavation points of an oil pipeline in southwest China. Methods Through the on-site testing and laboratory analysis on phys-chemical properties of soil and composition of corrosion prod-uct. Results The soil is slightly basic for the excavation point A, and its corrosivity is weak, as a result, where the pipeline suffer weakly uniform corrosion, and the corrosion products are mainly iron oxides, including FeO(OH), Fe(OH) 3 and Fe3 O4 , also the cathodic reaction is reduction of dissolved oxygen. While for excavation point B, because of the strong acidity and high content of sulfate ion, the soil is highly corrosive and makes the pipeline suffer serious pitting corrosion, and corrosion products are mainly composed by FeSO4 ·7H2 O, also contains a small amount of basic ferric sulfate, moreover the cathodic process is mainly the re-duction of hydrogen ions. Conclusion Due to the significant difference of the phys-chemical

通过静态浸泡腐蚀实验，采用扫描电子显微镜、X射线能谱仪、电化学实验等研究镁合金铈转化膜在0.05 mol/L NaCl溶液中的腐蚀行为，探讨膜层腐蚀机理。结果表明：随着浸泡时间的延长，膜层发生腐蚀和遭到破坏的程度也随之增强，浸泡初级腐蚀产物组织疏松，腐蚀后期腐蚀产物的致密性和紧实度增加；腐蚀产物主要由镁、氧等元素组成。随浸泡时间的延长，膜层电阻和腐蚀电位先增大后减小，腐蚀电流密度呈现先减小后增大的趋势。

The corrosion behavior and corrosion mechanism of the cerium conversion coating on magnesium alloy in 0.05 mol/L NaCl solution were investigated by using static immersing corrosion test, scanning electron microscope, energy dispersive spectrometer and electrochemical methods. The results show that with increasing the immersion time, the corrosion and damage degree of coating increase. The initial corrosion product is loose and the density and compactness of the coating corrosion products of coating increase, the main compositions of corrosion product, are Mg and O elements. The film resistance and corrosion potential increase at the first stage, and then decrease with increasing the immersion time, while the corrosion current density changes in the opposite tendency.

地下管线服役期内发生穿孔失效将会造成严重的安全事故及巨大的经济损失。某厂X60钢管线埋地一年后,7.1mm厚的管身出现蚀孔漏气现象。通过现场调研及SEM、XRD取样分析,研究了管壁穿孔失效的腐蚀机制。结果表明:蚀孔全部呈直线状分布于管底,蚀孔附近的腐蚀产物表面含有大量硫、氯元素;EDS及XRD分析确认腐蚀产物为硫铁化合物;钢管内壁基体侧氧化铁皮中含有大量FeO(OH)腐蚀产物。综合现场腐蚀环境、腐蚀形貌及腐蚀产物的详细分析,明确了蚀孔产生的原因为硫酸盐还原菌造成的微生物腐蚀,结合腐蚀特点及现场情况提出了改进措施。

Pitting in the body of underground pipelines and the failure during their service period will result in serious security incidents and huge economic loss.There appeared pitting in the body of X60 pipeline with the thickness of 7.1mm after 13 months of service,which resulted in air leakage.The corrosion mechanism of the pipeline body pitting was researched through site investigation and sample analysis by SEM and XRD.The results showed that all corrosion holes were located in the bottom of the pipeline in a straight line shape,plenty of S and Cl elements were found in the corrosion product around the holes,which was confirmed as FexSy through EDS and XRD analyses.A plenty of FeO(OH)were found in the scales beside the pipeline body.The cause of the corrosion holes was confirmed with the combination analyses of site environment,corrosion morphology and corrosion products to be microbiological corrosion due to SRB.Improvement measures were proposed according to the corrosion char

利用美国CORTEST公司高温高压反应釜模拟高含S油气田H2S/CO2腐蚀环境，在流动高矿化度饱和H2S/CO2介质中进行试验，辅以SEM、 XRD、动电位扫描及交流阻抗等表面分析和电化学技术，探讨了油管钢在高温高压H2S/CO2环境中的二次腐蚀行为。结果表明，普通N80油管钢单一CO2腐蚀速率较高，为1.89 mm/a；先CO2腐蚀后H2S腐蚀，腐蚀速率减小为1.38 mm/a，材料的腐蚀类型表现出严重的局部腐蚀，先生成的FeCO3膜转变为FeS膜，转变过程中腐蚀产物膜的晶格发生畸变，导致腐蚀产物膜分层、疏松且容易脱落；先H2S腐蚀后再CO2腐蚀，腐蚀速率明显减小至0.27 mm/a，腐蚀产物膜未发生转变，通过腐蚀产物膜电化学测试分析， FeCO3膜对基体的保护性差，而FeS膜对基体的保护性相对较好。

H2S/CO2 corrosion environments in oil and gas field containing rich S were simulated in a high temperature and high pressure autoclave manufactured by USA Cortest Company,and tests were conducted in flowing medium with high salinity. Second corrosion behavior of oil tube steel in high temperature and high pressure H2S/CO2 corrosion environments was analyzed and discussed by the following technologies,such as SEM,XRD,dynamic potential scanning,AC impedance and electrochemical techniques. The results showed that corrosion rate of N80 oil tube steel was very high,up to 1.89 mm/a. when solution immersion environment contain only CO2. If H2S corrosion was conducted after CO2 corrosion, the corrosion rate reduced to 1.38 mm/a. The corrosion type showed distinct characteristic of local corrosion. FeCO3 corrosion film formed firstly would be transformed to FeS film,in this process,aberration of crystal lattice happened,which would result in delamination and loosen of film. If CO2 cor