钢的高温高压CO2腐蚀产物膜研究进展

综述了近期国内外在CO2腐蚀产物膜方面的研究进展.其中重点阐述了钢在高温高压CO2环境中腐蚀产物膜的形成机理、主要影响因素、结构沉积过程,力学性能及电化学行为等,并讨论了有关CO2腐蚀产物膜方面的研究方向与内容.     

高温水中Zn2+注入抑制镍基合金腐蚀的研究

压水堆压力容器、管道、蒸汽发生器等结构材料在高温高压水环境中的腐蚀是影响核电站安全的重要因素,金属表面的氧化膜是影响其服役稳定与环境失效的关键,在含锌和钠离子的高温水溶液中制备了镍600合金的表面氧化膜,通过Mott-Schottky法分析了氧化膜的半导体性质,结合氧化膜制备前后镍600合金的质量指标,表明镍600合金...     

Cl~-对690合金在高温高压水中腐蚀行为的影响

采用扫描电子显微镜和X射线衍射仪研究了Cl-对690合金在高温高压水中腐蚀行为的影响。研究表明:690合金内外表面状态对其腐蚀形貌有显著影响,Cl-使得表面形成的钝化膜不均匀,出现较多的点蚀坑。溶液中的Cl-能够影响腐蚀产物膜的结构。当溶液中不含有Cl-时,腐蚀产物膜为双层结构,外层腐蚀产物为颗粒状;当溶液中含有Cl-时,腐蚀产物膜具有单层结构。XRD结果表明:两种环境中的钝化膜产物主要由Cr2O3、NiFe2O4、NiO等氧化物组成,但含Cl-条件下的氧化物较少。     

天然气井CO2分压对油管腐蚀行为的影响

CO2腐蚀是威胁油气开采过程中井下管柱服役安全的重要因素。本工作采用高温高压腐蚀模拟试验,研究了CO2分压对N80钢CO2腐蚀行为的影响。结果表明,在CO2腐蚀较为敏感的80℃时,N80钢腐蚀速率随CO2分压升高而上升,腐蚀类型与腐蚀产物膜形貌随CO2分压增加而变化,在相对低CO2分压下以全面腐蚀为主,高CO2分压下腐蚀类型由全面腐蚀转变为局部腐蚀。腐蚀产物膜的局部损伤是导致金属基体表面局部腐蚀的重要诱因。     

690合金在含Pb高温高压水中的腐蚀产物膜

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。     

抗硫碳钢在CO2/H2S条件下腐蚀产物膜特性及对腐蚀的影响

利用自制的高温高压釜,通过失重法、ESEM和EDS等分析技术研究了抗硫碳钢在高温高压CO2/H2S溶液中腐蚀产物膜特性及对腐蚀的影响.结果表明:抗硫碳钢在120℃不同介质条件下腐蚀产物膜的特性对材料的腐蚀有着决定性的作用,分别在CO2,H2S,CO2/H2S条件下,产物膜变得致密,晶柱变细,以无序状堆积,这种致密的腐蚀产物膜具有很好的保护性,降低了碳钢的腐蚀;当加入0.5%HAC时,腐蚀速率明显增大,从其表面膜的组成可以看出,Fe的硫化物含量有所减少,而表面膜中Cr、W的含量增加,使表面膜的骨架更加致密,但是,pH值的降低,加速了膜的溶解,在一定程度上使腐蚀速率比3%NaCl H2S 0.45MPaCO2增加;腐蚀产物膜结构、性质和组成对腐蚀速率有着重要的影响.     

温度对N80钢CO_2腐蚀产物膜结构和力学性能的影响

利用高温高压釜,以油田地层水为腐蚀介质,以高温高压气水两相为腐蚀环境,在N80油套管钢上生成CO2腐蚀产物膜,研究了65～115℃温度范围内腐蚀产物膜的结构和力学特性.结果表明:当温度在65～90℃时,腐蚀产物膜的主要成分为(Fe,Ca)CO3;在115℃时,膜的主要成分为(Fe,Ca,Mg)CO3和Fe3O4.随温度的升高,腐蚀产物膜的各项力学性能,如硬度、杨氏模量、断裂韧性以及膜与基体的结合强度均显示出升高的趋势.     

低铬X65管线钢CO2腐蚀产物膜的特征及形成机制

利用高温高压CO2腐蚀模拟实验以及ESEM,EDS,XPS和SEM等分析技术,研究了4种不同含Cr量的X65管线钢的腐蚀速率、腐蚀形态和腐蚀产物膜结构特征.结果表明:含Cr量高的钢平均腐蚀速率小,无Cr和含1%Cr的钢的腐蚀形态为局部腐蚀,含3%和5%Cr的钢的腐蚀形态为全面腐蚀.在高温高压CO2腐蚀环境中,含Cr钢的腐蚀产物膜为FleCO3和Cr(OH)3竞争沉积形成的多层结构,其中1Cr-X65和3Cr-X65的腐蚀膜具有3层结构,5Cr-X65的腐蚀膜是双层结构.Cr在腐蚀产物膜层中出现局部富集,远高于基体中的Cr含量.高含Cr量使腐蚀产物膜中的Cr(OH)3含量高,并提高了腐蚀膜的保护性能,从而引起腐蚀形态发生转变,腐蚀速率降低.FeCO3和Cr(OH)a共沉积层膜对低铬钢的抗CO2腐蚀性能具有关键的影响.     

缝隙腐蚀研究进展及核电材料的缝隙腐蚀问题

综述了缝隙腐蚀的主要机理、模拟研究技术及影响因素,介绍了核电材料在实际服役过程中的缝隙腐蚀问题,讨论了高温高压水环境下缝隙腐蚀研究存在的主要问题以及进一步的研究方向。     

温度对P110钢CO2腐蚀行为的影响

在模拟油田实际腐蚀环境中研究了温度对P110钢CO2腐蚀行为的影响．用SEM、XRD等分析了在不同温度条件下材料表面腐蚀产物膜的形貌以及对腐蚀速率和腐蚀形态的影响．结果表明，40℃时表层腐蚀产物类似于疏松的土壤，少且很松散地附着在材料表面，成份主要是溶液中沉积的KCl.90℃时腐蚀产物主要是钙铁镁的碳酸盐和少量的KCl和Fe2O3，腐蚀产物呈颗粒状，较致密但是膜层中含有大量的孔洞．140℃时，试样表层腐蚀产物呈致密的粘土形貌、下层腐蚀产物仍是颗粒状，产物层致密，成份主要是FeCO3和KCl．不同温度下不同的腐蚀产物形貌造成随温度升高。材料的平均腐蚀速率在90℃时出现峰值．     

水冷壁管在CPT和NaOH水工况下的腐蚀特征

本文使用电化学工作站、XRD、SEM和EDS等方法,研究水冷壁管在CPT和CT处理下高温腐蚀特性,分析其形成机理,为电站化学工作者在选择水工况和金属防护方面提供一定的参考。结果表明:CPT条件下金属内壁表层呈现了较深的腐蚀坑(腐蚀深度达到了200μm)和凹凸不平的特征,有明显的冲刷痕迹,不均匀的氧化物颗粒镶嵌在金属表层处;CT形成的氧化物具有明显的8面体晶体结构,腐蚀深度在10μm左右,氧化物颗粒较大,不紧凑,中间存在多而大的孔隙,容易引起缝隙腐蚀,颗粒物的脱落也会对水质起到破坏作用。     

溶解氢对316L不锈钢在模拟压水堆一回路水中氧化行为的影响

采用扫描电镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)和透射电镜(TEM)分析了不同溶解氢含量下, 316L不锈钢在325℃的模拟压水堆一回路水中形成的氧化膜的形貌、结构和成份。实验结果表明, 316L不锈钢在溶解氢含量为零的高温高压水中形成外层富铁,内层富铬的双层氧化膜。随着水中溶解氢含量的升高,氧化膜外层的大颗粒氧化物尺寸减小,排列更加致密。而氧化膜的物相组成变化不明显,均主要是由尖晶石结构氧化物构成。XPS分析表明,随着水中溶解氢含量的升高,氧化膜厚度逐渐增加,且氧化膜中Ni含量升高,Cr含量降低。     

Hydrogen evolution and corrosion behavior of zirconium tubing in sub- and supercritical water

Hydrogen evolution is inevitable during the oxidation of zirconium in high-temperature water. A fraction of this evolved hydrogen diffuses into the cladding material, and the remaining is carried away by the reactor coolant. In this study, hydrogen evolution and corrosion behavior of zirconium-702 in high-temperature water are investigated using a continuous tubular flow-through reactor. The results show that at a constant pressure of 25 MPa, the evolution of hydrogen gas from an oxidized zirconium reactor surface is approximately 24 times larger at 500°C than at 350°C. At higher temperatures, the zirconium reactor tubing exposed to water shows ballooning, with bending before the rupture near the exit end of the reactor tube, where the concentration of evolved hydrogen is the highest.     

Fe/Cr涂层抗热腐蚀性能研究

设计制造出Fe/Cr粉芯丝材,利用电弧喷涂技术制备出耐高温腐蚀的工作涂层。运用光学显微镜、扫描电子显微镜(SEM)、X射线衍射仪(XRD)等研究了电弧喷涂Fe/Cr合金涂层的微观结构、腐蚀动力学和高温下的腐蚀性能。结果表明,该涂层组织致密,涂层中形成Cr2O3或尖晶石型氧化物是其具有优异的抗高温腐蚀性能的主要原因,涂层抗高温腐蚀性能较好。     

Das Korrosionsverhalten der Nickelbasislegierung Inconel 625

The corrosion behaviour of the nickel-based alloy Inconel 625 Due to its high resistance to corrosion by reactor coolants, water vapour and liquid sodium, the new high-temperature resistant nickel alloy Inconel 625 is well suited as fuel cladding material for a reactor of high energy density. Up to above 800° C, the scaling resistance in air is good. In electrolyte solutions, the general corrosion under conditions where a passivation layer cannot be formed or maintained is relatively slow. In accordance with expectations, Inconel 625 is not subject to intercrystalline corrosion by Strauss solutions even in the thermally sensitized condition, and even the reaction with nitric acid containing Cr^VI ions is not so much intergranular but superficial. If the material, together with V2A steel, is in contact with liquid sodium of 600° C, it is prone to chemical mass transfer. As a result, there occur precipitations of a new crystalline phase at the grain boundaries of the the Inconel 625 surface.     

F28不锈钢在尿素介质中形成的钝化膜研究

采用XPS和AES技术研究了F28低偏析奥氏体不锈钢在尿素合成介质中形成的钝化膜,并与化学成分类似的Sanicro28合金在相同条件下形成的钝化膜作了对比.结果表明,降低磷、硫和硅等杂质元素的偏析,使钢抗腐蚀性能提高的原因在于增加了钝化膜的Cr2O3含量,改善了钝化膜的防护能力.     

注锌对316L奥氏体不锈钢氧化膜成分的影响

通过模拟压水堆一回路水环境,对316L奥氏体不锈钢在320℃含锌10μg/kg的高温溶液中进行了1000 h的腐蚀实验,对腐蚀后的试样表面进行了XPS分析。结果表明,试样在含锌溶液中形成了化学成分为(Zn,Fe,Ni)(Cr,Fe)2O4的致密氧化膜,随着腐蚀时间的增加,氧化膜中的富Cr区由内层扩展至整个氧化膜。     

Investigation on carbon dioxide corrosion behaviour of HP13Cr110 stainless steel in simulated stratum water

The carbon dioxide corrosion behaviour of HP13Cr110 stainless steel in simulated stratum water is studied by potentiodynamic curve and electrochemical impedance spectroscopy (EIS); the micro-structure and composition of the corrosion scale formed at high-temperature and high-pressure are analyzed by scanning electron microscopy (SEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results show that 13Cr stainless steel is in passive state in the stratum water, the passive current density increases and the passive potential region decreases with increasing temperature. The corrosion scale formed at high-temperature and high-pressure is mainly composed of iron/chromium oxides and a little amount of FeCO₃.     

Corrosion and Corrosion Control in Light Water Reactors

Serious corrosion problems have plagued the light water reactor (LWR) industry for decades. The complex corrosion mechanisms involved and the development of practical engineering solutions for their mitigation will be discussed in this article. After a brief overview of the basic designs of the boiling water reactor (BWR) and pressurized water reactor (PWR), emphasis will be placed on the general corrosion of LWR containments, flow-accelerated corrosion of carbon steel components, intergranular stress corrosion cracking (IGSCC) in BWRs, primary water stress corrosion cracking (PWSCC) in PWRs, and irradiation-assisted stress corrosion cracking (IASCC) in both systems. Finally, the corrosion future of both plants will be discussed as plants extend their period of operation for an additional 20 to 40 years.     

Corrosion behaviour of reactor coolant system materials in nuclear power plants

The materials used for the pressure‐retaining parts of reactor coolant system components in light water reactor nuclear power plants have to meet special requirements in terms of their mechanical properties, workability and in‐service performance. Corrosion issues play an important role in connection with plant operating conditions. While giving consideration to the specific service environment of the reactor whether a pressurized or boiling water reactor – the materials used for the individual components and the water chemistries employed in the various systems are selected such that metal loss due to general corrosion will remain very low. Thus the materials used in light water reactor plants exhibit a high general resistance to corrosion for their specified service conditions, material conditions and mechanical loads. However, under certain operating conditions other corrosion mechanisms may be found to induce damage. This paper uses data from the literature, published results of national and international research programs, information on damage which has actually occurred world‐wide and experience gained by Framatome ANP GmbH (former Siemens/KWU) in this field as a basis for discussing these mostly localised corrosion phenomena in terms of “classical” corrosion systems. Aspects associated with irradiation and its effects are not considered. Suitable remedial actions are, however, addressed wherever these are of relevance. The materials considered comprise unalloyed and low‐alloy steels, austenitic chromium‐nickel steels as well as high‐nickel steels and nickel‐base alloys which are exposed to the reactor coolant environment of boiling water reactor or pressurized water reactor plants, including materials investigated in corresponding water environments simulated in the laboratory.