Cu—Cr合金在H2—H2S混合气中的腐蚀行为

研究了Cu-Cr合金及纯铜、纯铬在500－600℃,硫分压为10^-5Pa时的硫化腐蚀。两种Cu-Cr合金的腐蚀速度均介于两种纯金属之间,并随温度的升高而增大,但在两种Cu-Cr合金的表面均形成了复杂的腐蚀产物膜,外层为Cu2S层,有时不连续甚至剥落,中间层为二元Cu-Cr硫化物CuCrS2,内层为二元Cu-Cr硫化物CuCr2S4和CrS的混合物,有时也包含未被腐蚀的金属铬颗粒。在腐蚀区以下的合金基体中没有铬的贫化现象发生。这种腐蚀膜结构的形成是合金中存在两相的结果。     

Effect of tin on high-temperature sulphidation of Fe-Cr alloys in H2/H2S atmospheres

The high temperature sulphidation behaviour of Fe-46Cr-xSn (x = 0; 0.2; 0.5; 1; 2) alloys has been studied at temperatures of 1073, 1173 and 1273 K in H₂/H₂S mixtures with different sulphur vapour partial pressures of 10⁻¹, 10⁻³ and 10⁻⁵ Pa. Thermogravimetric studies in combination with scanning electron microscope (SEM), with energy dispersive spectrometer (EDS), and X-ray diffraction (XRD) techniques, have displayed a significant influence of the sulphur partial pressure on the composition and growth rate of the sulphide scale. The results have shown that addition of tin increases the sulphidation rate of Fe-46Cr alloys but not considerably (except at temperatures of 1073 and 1173 K combined with sulphur partial pressure of 10⁻⁵ Pa). The metallic core of the studied samples was enriched in tin and iron, moreover tin was found in the internal layer close to the metallic core as metallic Fe_xSn_y inclusions with tin concentrations of up to 12 at.%.     

Ni-Fe-P镀层在H2S/CO2腐蚀环境中的腐蚀电化学研究

在油管常用钢N80钢表面制备了Ni-Fe-P化学镀层,采用SEM、EDS、XRD等分析手段,对所制备镀层的成分、微观形貌、结构等性能进行了分析研究;采用电化学方法评价了Ni-Fe-P镀层在H2S/CO2溶液中的耐蚀性。结果表明,N80钢表面经过化学镀Ni-Fe-P处理后,其耐蚀性得到很大的提高,镀层结构为非晶态;电化学测试结果表明该镀层在H2S/CO2溶液中具有极强的钝化倾向和很好的耐酸性,结果均证明Ni-Fe-P镀层具有良好的抗H2S/CO2腐蚀性能。     

Sulphidation of Cu and Cu-Ni alloys in H2S/argon mixture

The sulphidation of cold-worked Cu and annealed Cu and Cu-Ni alloys containing 10 and 50wt.%Ni, has been studied in dry H₂S/argon (1 : 20) mixture at 500°C for the cold-worked, and in the range 320–500°C for the annealed samples. The reaction kinetics were linear in all tests. The rate of sulphidation decreased with increasing amount of cold work. The scale on annealed sample showed considerable blister formation and grain growth which were appreciably less on samples with increasing cold work. There was no blister formation on alloys. From combined techniques of X-ray powder and diffractometry, the sulphide scale on Cu was found to be mainly Cu₂S, while that on the alloys a thick scale of Ni₃S₂ was associated with a thin layer of Cu₂S. Of the two alloys, Cu-10%Ni sulphidized faster than Cu-50%Ni at all temperatures. The activation energy of sulphidation of annealed Cu was about 74 kJ/mole compared with 40 kJ/mole for the alloy. The dissociation of the adsorbed gas at the gas/scale interface is considered to be the rate-controlling process for the linear kinetics.     

Scanning photoelectrochemical analysis of hydrogen permeation on ASTM A516 grade60 steel welded joints in a H2S containing solution

Hydrogen permeation through a welded joint of an ASTM A516 grade60 steel immersed in a H₂S solution was investigated using the scanning photoelectrochemical microscopy, an in situ technique providing images of the spatial distribution of hydrogen diffusion in real time and with good resolution. The paper presents images of hydrogen spatial distribution in the material including the base metal and heat-affected zone. Electrochemical impedance measurements were also performed in order to complement the information obtained.     

暂态技术研究高含H2S和CO2近中性溶液中套管钢的界面反应

采用电位阶跃技术研究在H2S和CO2共存的近中性溶液中套管钢/溶液界面和反应过程。应用数学模型分析界面反应中氢吸附过程、负离子脱附过程和氢吸收过程的变化规律。当阶跃电位为50mV,界面反应由氢吸附过程控制,当阶跃电位超过50mV,界面反应由负离子脱附过程控制。研究显示,在含50%H2S(pH=5.9)环境中,加入CO2提高了界面负离子脱附、氢吸附和氢吸收反应速率。     

High temperature corrosion mechanisms of certain new TiAl-based intermetallic alloys in an aggressive H2/H2O/H2S environment at 850 °C

High temperature corrosion behaviour of three TiAl-based intermetallic alloys - Ti-44Al-8Nb-1B, Ti-46Al-8Nb-1B and Ti-48Al-2Nb-2Cr-1B (at.%) - was studied in an environment of H₂/H₂S/H₂O yielding p_S2 ∼ 6.8 × 10⁻¹ Pa and p_O2 ∼ 1.2 × 10⁻¹⁵ Pa potentials at 850 °C. The kinetic results obtained by a discontinuous gravimetric method indicate that increase in Al and Nb concentrations led to enhanced high temperature corrosion resistance, the corrosion resistance decreasing in the order: Ti-46Al-8Nb-1B > Ti-44Al-8Nb-1B > Ti-48Al-2Nb-2Cr-1B. The scale development studies using SEM, TEM, EDX, WDS and XRD confirmed the formation of a multilayered scale on all materials. An outer layer consisting of TiO₂ existed beneath which an Al₂O₃ layer was present. Then a layer of TiO₂ formed again, below which an Al-enriched NbAl₃ was observed. A TiS layer was found beneath the NbAl₃ layer. The formation of TiS led to the development of a NbAl₃ band between the multilayered scale and the substrate.     

湿H2S环境下低合金钢焊接接头氢扩散数值模拟

利用电化学渗透法测定了氢在16MnR低合金钢焊接接头处的焊缝金属、热影响区金属以及母材中的扩散系数.利用有限元软件ABAQUS,对16MnR钢焊接接头氢扩散进行数值模拟,考虑焊接残余应力、不同组织对氢扩散的影响,得到焊接接头扩散氢的浓度随时间的分布.结果表明,在焊缝和热影响区,氢的扩散系数和焊接残余应力较大,使氢在焊缝和热影响区聚集,降低材料的力学性能,使得焊接接头部位成为最薄弱环节,在湿H2S环境下很容易发生与氢有关的损伤和破坏.     

H2S/CO2环境中L360钢点蚀行为研究

利用静态挂片失重法研究了含H₂S/CO₂模拟油田水溶液中, 温度及Cl^-浓度对L360管线钢点蚀的影响, 并利用Gumbel第一类近似函数分析了最深蚀孔概率. 结果表明, 在40℃~70℃之间, Cl^-浓度为10 g/L条件下, 点蚀的严重程度随温度增高而增大. 恒定温度下, Cl^-浓度对点蚀发生也有明显的影响, 当Cl^-在10×15 g/L范围时, 腐蚀试样发生明显的点蚀; 当Cl^-浓度大于20 g/L时, 试样主要发生均匀腐蚀, 随着Cl^-浓度的增大, 腐蚀产物膜变得更加疏松, 保护性能下降, 均匀腐蚀速率增大. 最深点蚀分布服从Gumbel第一类近似函数.     

P110钢在CO2／H2S环境中的适用性研究

采用高温高压实验设备辅以失重法,研究了CO2／H2S腐蚀环境中P110钢的腐蚀性能,用SEM、EDS和XRD等分析了腐蚀产物．分别用电化学充氢及NACE TM0177A法对P110钢进行耐氢损伤试验．结果表明,虽然P110钢在试验环境中的均匀腐蚀速率很小,未发生点蚀,但随着充氢量的增加,强度、伸长率及断面收缩率均降低．...     

基于人工神经网络的CO2/H2S腐蚀速率预测模型

探索对油气管线CO2/H2S腐蚀速率的预测,应用LabVIEW软件中的MATLAB Script节点,通过Lab-VIEW与MATLAB混合编程构建了虚拟仪器程序,建立了油气管线腐蚀速率预测的BP神经网络模型。数值仿真试验结果表明,建立的模型稳定性好,预测精度高,使用效果良好。     

镍基合金718在H2S/CO2环境中的腐蚀行为研究

运用腐蚀失重和电化学测量技术,研究了镍基合金718在模拟苛刻油田环境中的H₂S/CO₂腐蚀行为。结果表明,在模拟高温高压H₂S/CO₂腐蚀环境中,718合金腐蚀轻微,表现出良好的抗均匀腐蚀和局部腐蚀能力。电化学测试结果表明,在模拟CO₂腐蚀环境中,718合金的阳极极化曲线存在明显的钝化区,而在模拟H₂S/CO₂腐蚀条件下的阳极极化曲线呈现多次活化-钝化转变现象,表明腐蚀产物膜的稳定性降低;EIS表明阻抗谱均有明显的容抗弧特征,不含H₂S时材料显示单一的容抗弧,加入H₂S时低频显示扩散阻抗控制,饱和CO₂溶液中718合金具有相对较大的极化电阻。     

含硫天然气管线H2S/CO2腐蚀发展规律

在模拟川渝地区天然气管线含H2S/CO2介质环境中进行腐蚀实验研究,分析了X52钢在含H2S/CO2溶液介质中暴露时间对管线钢腐蚀速率、腐蚀产物膜形貌及组成的影响。结果表明,随暴露时间延长,腐蚀产物膜层对基体产生一定保护性,减缓了腐蚀进程。腐蚀产物由马基诺矿型、硫化亚铁和陨硫铁发展成马基诺矿、硫化亚铁、陨硫铁和黄铁矿。     

Polarization of the H2, CO, CO2|Ni and H2S, H2, CO, CO2|Ni electrodes in molten sodium carbonate

Reactions at the H₂,CO,CO₂,Ni and H₂S,H₂,CO,CO₂|Ni electrodes in molten sodium carbonate at 1000°C have been studied in detail by means of computer-assisted analysis of potentiostatic polarization curves. Calculated curves accounting for charge transfer polarization, concentration polarization, ohmic loss and passivation arc matched to experimental curves by a series of successive approximations. Kinetic parameters thus determined are interpreted via rate theory and hypotheses concerning the identity of individual electrode reactions. Previous work with the CO,CO₂|Ni electrode was satisfactorily modelled by five anodic reactions: oxidation of physically dissolved CO, oxidation of chemically dissolved CO, oxidation of Ni to Ni²⁺, oxidation of NiO to Ni₂O₃ and oxidation of carbonate, occurring at progressively increasing overpotentials. At the H₂,CO,CO₂|Ni electrode, in addition to these reactions (oxidation of physically dissolved CO was not seen at the P_co values employed) oxidation of H₂ was observed at low anodic overpotentials. These experiments also clearly delineated an additional reaction postulated to be oxidation of Ni₂O₃ to NiO₂. Reactions at the H₂S,H₂,CO,CO₂|Ni electrode were identical to those at the H₂,CO,CO₂|Ni electrode save that the diffusion-limited current for oxidation of chemically dissolved CO increased linearly with . This is attributed to the occurrence of chemically dissolved CO as a sulfide species, e.g. COHS⁻, in addition to the CO₂^2- found under CO, CO₂ atmospheres. In support of this mechanism, the reaction did not display diffusion control when 0.5% Na₂S was added to the electrolyte, suggesting a high level of, e.g., COS^2-. Total cell pressure was 1 atm; in the sulfide experiments P_H2S varied from 0.000027 to 0.027 atm, with P_{H2 = 0.5 atm} and P_co = P_co2 = 0.25 atm.     

X65钢海底管道在CO2/H2S腐蚀环境下的适用性

利用高温高压反应釜模拟试验和电化学测试,研究了X65钢海底管道在CO2/H2S环境下的耐蚀性。结果表明,不加缓蚀剂条件下,X65钢在总压为0.25MPa时的平均腐蚀速率及局部腐蚀风险与总压为0.7MPa时相比,均显著降低。添加100mg/L的缓蚀剂,X65钢的腐蚀速率显著降低,缓蚀效果较好;电化学测试与模拟试验结果一致。降压至0.25MPa分离出部分腐蚀性气体后再输送可大大降低内腐蚀风险,结合缓蚀剂措施,该腐蚀环境下可选择X65钢海底管道输送油气。     

L360钢在H2S/CO2环境中腐蚀的预测

运用BP人工神经网络技术建立了预测L360钢在H₂S/CO₂环境中腐蚀的模型,神经网络拓扑结构为5-4-1,网络模型训练成功以后,应用它预测L360钢在H₂S/CO₂中的腐蚀速度.结果表明,人工神经网络模型预测的结果与实验数据相当符合,误差在14%以内.由此可见,BP神经网络模型可以作为预测H₂S/CO₂环境致集输管线腐蚀速率的工具.     

Oxide and sulphide layers on copper exposed to H2S containing moist air

A coulometric method was used to follow the growth of the corrosion layer on copper, in well defined conditions, by varying the H₂S concentration, the temperature and the level of relative humidity. A high H₂S concentration favours the formation of both, oxide and sulphide. Copper oxide was found to be more sensitive to humidity than copper sulphide. Thus corrosion compounds enriched in oxides instead of sulphides were observed at high relative humidity. This behaviour is discussed on the basis of a different mechanism of formation for the two copper compounds.     

CO2对H2S／CO2环境中P110钢应力腐蚀的影响研究

采用恒载荷拉伸法、腐蚀电化学测试和断口分析技术等,研究了P110钢在不同H2S／CO2含量的NACE-A溶液中的硫化物应力腐蚀（SSCC）行为．结果表明,在加载初期,P110钢的自腐蚀电位Ecorr）急剧下降,至极小值后缓慢升高,达到稳定值后直至断裂,试样断口呈脆性解理状．当通入CO2量达到17％时,P110钢的自腐蚀...     

Influence of dynamic straining on hydrogen embrittlement of UNS-G41300 and UNS-S31803 steels in a low H2S concentration environment

The hydrogen embrittlement of UNS-G41300 and UNS-S31803 steels in sodium thiosulphate solutions was studied. Slow strain rate and electrochemical tests were used. The influence of elastic and plastic strain on the hydrogen embrittlement process of these materials was investigated.The results showed that thiosulphate solutions efficiently simulate an aggressive environment containing low concentrations of hydrogen sulfide, being effective in promoting the embrittlement of the UNS-G41300 steel. For this tempered martensitic steel, under the test conditions, the role of a dynamic process of plastic straining on its hydrogen embrittlement was demonstrated.For the UNS-S31803 steel, a duplex (austenitic-ferritic) stainless steel, the study of the hydrogen embrittlement with the solutions used required cathodic polarization and showed that the embrittlement preferably occurs in the ferritic phase.     

The sulphidation properties of titanium-, manganese- and niobium-bearing Fe---25Cr alloys in H2---H2S mixtures at 800°C

An investigation of high-temperature sulphidation properties of 4 wt% Ti-, 9 wt% Mn- and 8 wt% Nb-bearing Fe---25Cr alloys has been carried out in H₂-H₂S mixtures of sulphur partial pressure in the range of 10⁻³ < pS₂ < I Pa at 800°C. On the whole, the sulphidation kinetics of all alloys obeyed the parabolic law after the initial period of reaction. In some cases, fluctuations in the weight gain-time curves arose due to cracking of sulphide scales. Compared with the weight gain of Fe---25Cr alloy, the additions of alloying elements improved the sulphidation resistance. The effect of 8 wt% Nb was relatively major, but the effects of 4 wt% Ti and 9 wt% Mn were minimal. The addition of these elements did not change the surface morphologies or improve the structure of sulphide scales. Combining the sulphidation kinetics and the analysis of sulphide scale structure, the sulphidation mechanisms of these Fe---25Cr-base alloys have been proposed and the effects of titanium, manganese and niobium have been discussed.