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1.
化学镀Ni┐P/Fe双层结构材料中氢的扩散 总被引:1,自引:0,他引:1
采用超高真空气相氢渗透技术在80~250℃温度范围内,测定了氢在化学镀非晶态Ni-P/Fe双层结构材料中的扩散系数,研究了化学镀Ni-P镀层及其在300℃下真空退火热处理1h后对氢在基材中扩散行为的影响。结果表明,在实验温度范围内,氢在化学镀Ni-P/Fe双层结构中的有效扩散系数D与温度T的关系遵循Arrhenius方程,300℃真空退火处理后,有效扩散系数基本不变。 相似文献
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氢在21-6-9奥氏体不锈钢中的渗透 总被引:3,自引:1,他引:2
本工作采用超高真空气相渗透-动态监测技术,研究了氢在21-6-9奥氏体不锈钢中的渗透。结果指出:在230~430℃范围内,氢渗透率、扩散系数和溶解度常数与温度的关系遵循Arrhenius方程;试样两面电镀钯,可以防止表面氧化作用对氢渗透的影响,稳态渗透速度与充氢压力的平方根成正比;试样的冷加工和热处理状态对材料的氢渗透行为没有影响。 相似文献
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合金成分和热处理对奥氏体不锈钢氢渗透行为的影响 总被引:1,自引:0,他引:1
本工作采用超高真空-气相渗透技术,在200—430℃范围内,测定了氢在316L,316LN,21-6-9,21-9-9,304和1Cr18Ni9Ti等六种奥氏体不锈钢中的渗透率、扩散系数和溶解度常数,研究了合金成分和材料的冷加工、热处理状态对氢渗透行为的影响.结果指出,氢在各合金中的渗透率和扩散系数在实验温度范围内均遵循Arrhenius方程,材料的冷加工和热处理状态对氢渗透行为没有明显影响,合金成分略有影响.讨论了奥氏体不锈钢与纯铁、一般低合金钢氢渗透行为的差别. 相似文献
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氢在2.25Cr—1Mo耐热钢中的扩散规律 总被引:1,自引:0,他引:1
采用电化学渗氢的方法研究了加氢反应器简体2.25Cr-1Mo钢中氢的扩散现律试样的厚度低于1.6mm时,随着厚度的增加,扩散系数D值增大;当厚度大于1.6mm后,D值稳定不变实验测得温度与扩散系数的关系为此式可用于在运行状态下的加氢反应器器壁中氢渗透原子氢浓度分布的计算 相似文献
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渗铝钢的抗氢损伤性能 总被引:1,自引:0,他引:1
采用钝化助镀法在30CrMo钢表面获得热浸铝层,通过扩散渗铝和调质处理获得了渗铝钢试片和试棒.用氢渗透电化学技术测量了渗铝钢在饱和H2S盐水中的渗氢曲线,得到了不同温度(T)下氢在渗铝钢中的扩散系数(D),拟合得到了T与D的关系式,并研究了溶液中NaCl和CO2对稳态氢渗透电流(Imax)的影响.比较了30CrMo渗铝钢在饱和H2S盐水中腐蚀前后的机械性能.结果表明:热浸渗铝钢对氢扩散有明显的阻滞作用,其抗氢损伤性能好于基体钢材. 相似文献
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对理想晶体中的H扩散通量与充H时间的关系式进行修正,并用修正后的公式直接从实验数据中拟合H在材料中的扩散系数和穿透时间,结果表明,用理想晶体中H扩散通量随充H时间变化的修正关系式可以表征实际材料在电化学充H过程中的H原子扩散通量随充H时间变化的关系曲线,也可以用以研究实际材料中H陷阱对H原子扩散系数的作用.用修正后的公式对20g纯净钢电化学充H实验数据进行最小二乘法拟合,直接得到H原子在不同H陷阱状态20g纯净钢中的扩散系数和穿透时间.拟合结果显示:20g纯净钢中的不可逆H陷阱对H原子的扩散系数没有影响,只是延长了H原子的穿透时间,而可逆H陷阱则降低了H原子的扩散系数. 相似文献
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镀镍碳钢在高温无氧水中的腐蚀电化学行为 总被引:1,自引:0,他引:1
利用线性极化法、极化曲线法和交流阻抗技术研究了化学镀非晶态Ni-P和电镀纳米Ni处理的碳钢在高温无氧水中的腐蚀电化学行为.结果表明,功能镀镍薄膜/碳钢复合材料在高温无氧水中的腐蚀是在电偶腐蚀条件下因氢去极化引起的电化学腐蚀,腐蚀的特征是点蚀,腐蚀的程度取决于镀层的均匀程度和镀层自身的耐蚀能力. 相似文献
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L. E. Tsygankova V. I. Vigdorovich A. A. Zvereva V. I. Kichigin 《Protection of Metals and Physical Chemistry of Surfaces》2016,52(2):211-217
Accumulation of electrolytic hydrogen in alkaline medium (5 M KOH) by multiwall carbon nanotubes (MWCNTs) 20–60 nm in inner diameter and 2 μm in length obtained by catalytic pyrolysis of propane/butane mixture has been studied by means of the electrochemical diffusion technique, cyclic voltammetry, and impedance spectroscopy. MWCNTs were applied on a steel membrane and were encapsulated by a 10-nm electrolytic nickel layer. Cyclic voltammograms were recorded in the range of potentials from ?1.2 to +0.2 V and contained a current peak in the cathode region corresponding to hydrogen absorption by nanotubes at ?0.9 V and current peak in the anode region corresponding to oxidation of absorbed hydrogen at ?0.6 V. Hydrogen storage capacity of MWCNTs varies from 4.6 to 6.5% depending on the amount of nanotubes according to electrochemical diffusion data. The electrochemical impedance data correlate with the results of the above methods. 相似文献
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《Science & Technology of Welding & Joining》2013,18(4):497-502
AbstractConstant heating rate hydrogen thermal analyses were carried out for weld metals with tensile strengths in the range 490–1000 MPa. It was found that the hydrogen diffusion rate in the highest strength weld metal is lower by a factor of five than that in a lower strength variant. The hydrogen diffusion behaviour varied greatly between weld metal and wrought steel. Finite difference analyses indicated that this difference can be attributed to the changes in the interaction energy between a trap site and hydrogen. Using the analysis it was possible to determine apparent diffusion rates at temperatures from 20 to 300°C and explain satisfactorily the effect of plastic deformation on hydrogen diffusion in a steel. 相似文献
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Electrochemical permeation technique and thermal desorption spectroscopy were used to evaluate the hydrogen diffusion, solubility, and trapping behaviour in nitrogen containing austenitic alloys. The hydrogen diffusion of all alloys obeyed Arrhenius relationships in the studied experimental temperature range. The apparent diffusion coefficients were determined and the relevant activation energies were estimated. Nitrogen at higher concentration (>0.38 wt.%) as well as chromium decrease the hydrogen diffusion whereas nickel has opposite effect. The thermal analysis of all alloys except Cr18Mn18N0.57 shows a main single peak at different heating rates indicating no significant hydrogen interaction with microstructural defects. The alloy Cr18Mn18N shows a shoulder in addition to the peak which is attributed to nitrogen–hydrogen interaction. The activation energy estimated from the thermal analysis is nearly equal to the activation energy for diffusion obtained from the Arrhenius plots of the corresponding alloys. 相似文献
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Stéphane Haag 《Surface & coatings technology》2006,201(6):2166-2173
This work concerns the preparation and characterization of a composite inorganic membrane based on nickel supported on a tubular porous ceramic for use in high temperature hydrogen separation. The characteristics required of this material for a high hydrogen permselectivity are a defect-free coating and thermal stability. Thus, electroless plating of nickel using hydrazine as reducing agent enables a metallic nickel coating to be deposited directly on an asymmetric alumina support having a mesoporous top layer composed of γ-alumina. To optimize conditions for reduction of the metal ion, variables including the temperature, the nature of the nickel salt, the choice of stabilizer and the hydrazine concentrations in the plating bath were studied. Metallic nickel was found to be dispersed both in and on the γ-alumina. After heat treatment at high temperature, a thin and uniform pure Ni˙ layer (thickness ≈ 1-1.5 μm), characterized by scanning electron microscopy (SEM) and X-ray Diffraction (XRD), was formed. The separation performance of the Ni/ceramic membrane was investigated using single gases (hydrogen, nitrogen, carbon dioxide and methane) at room temperature. The results indicate that the mechanism of hydrogen transport is related to the Knudsen diffusion. 相似文献
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元素硫对特高含H2S气井用油管钢的腐蚀 总被引:3,自引:1,他引:3
用电化学方法研究了特高含硫化氢气井所用油管钢在含硫磺的5%NaCl水溶液中的电化学行为,湿态硫磺作为一种阴极去极化剂促进材料的腐蚀,腐蚀速度随硫磺含量增加而增加,且存在浓度极值。升温同样可促进硫磺对材料的腐蚀,不同温度腐蚀机理不同。 相似文献
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强度对钢SCC敏感性的影响 总被引:2,自引:1,他引:1
郑文龙 《中国腐蚀与防护学报》1984,4(4):287-294
通过对不同强度等级的40CrNiMo,50Mn 18Cr4MoVN,34CrNi3Mo钢的SCC研究,探讨了强度对不同机理SCC敏感性的影响规律。试验结果表明,强度对不同类型SCC的敏感性有着不同的影响。对于由氢脆和由强化相构成连续活性通道阳极溶解机理控制的SCC,提高强度使钢的抗SCC能力降低;而在塑性变形所控制下的SCC,提高钢的强度可以提高抗SCC的能力。 相似文献
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Sheng-guan Qu Fu-qiang Lai Guang-hong Wang Zhi-min Yuan Xiao-qiang Li Hui Guo 《Journal of Materials Engineering and Performance》2016,25(4):1407-1415
The friction and wear properties of 30CrMnSiA steel were investigated at elevated temperature from 100 to 600 °C. Thereafter, the wear debris and worn surfaces were examined to understand the wear mechanisms. The remained debris with relatively high hardness created three-body abrasion at lower temperatures (100-300 °C). Abrasive wear prevailed at the conditions with high friction coefficients and wear rates. A significant change in friction and wear behavior occurred at 400 °C. At the temperature of 400 °C, oxidation induced mild wear was found because of the formation of load-bearing oxide film. Both the friction coefficients and wear rates of the steel were lowest at 400 °C. At the temperatures of 500-600 °C, a mild-to-severe wear transition occurred which resulted in an increase in the friction coefficients and wear rates of the steel. This is related to the decrease in the strength of matrix and hardness of worn surfaces and subsurfaces. The predominant wear mechanism is considered to be severe abrasive, adhesive wear and a fatigue delamination of the oxide film. 相似文献
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外加电位对X70管线钢在库尔勒土壤模拟溶液中应力腐蚀开裂敏感性的影响 总被引:1,自引:0,他引:1
采用慢应变速率拉仲试验(SSRT)研究了不同外加电位下X70管线钢在库尔勒土壤模拟溶液中的应力腐蚀开裂(SCC)行为,并用扫描电镜分析了不同电位下的断面形貌.结果表明,X70管线钢在库尔勒土壤模拟溶液中具有SCC敏感性;在Ecorr附近施加弱极化时,应力腐蚀开裂敏感性增加;施加强阳极电位时,发生强烈阳极溶解,导致阳极溶解断裂;施加强阴极电位时,析氢过程加强,导致氢致应力腐蚀断裂. 相似文献