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为进一步了解7075型铝合金在碱性工作环境中的腐蚀行为,采用电化学方法研究了NaOH浓度、Cl-含量和温度对7075型铝合金在高低NaOH浓度的碱性NaCl溶液中的腐蚀行为。结果表明:低NaOH浓度(0.1~0.5 mol/L)时,铝合金表面以阻挡层(腐蚀产物附着层)的生长为主,NaOH浓度越高,阻挡层生成速率越大;高NaOH浓度(1.0~5.0 mol/L)时,铝合层表面以阻挡层的溶解为主,NaOH浓度越高,阻挡层受析氢破坏的程度越大;析氢对阻挡层的破坏作用在Cl-作用下有所加强,溶液中NaOH浓度越高,增强效果越明显;在0.04 mol/L NaOH+0.01 mol/L NaCl溶液中,温度主要影响阻挡层的生长,其生长速率随温度的升高而增加,在0.40 mol/L NaOH+0.01 NaCl溶液中,温度主要影响阻挡层的溶解,阻挡层受析氢破坏程度随温度升高而加大。 相似文献
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张大磊妙圆圆荆赫豆肖辉金有海 《材料研究学报》2018,(7):533-540
采用改进的Devanathan双面电解池检测了热镀锌钢材的氢渗透电流,结合慢应变速率拉伸试验和断口形貌分析,研究了受工业海洋大气污染有亚硫酸盐沉积的热镀锌钢材氢吸收行为及其在此环境中的氢脆敏感性。结果表明:随着试样表面亚硫酸盐的增加,其氢渗透电流显著增大;镀层缺陷使试样的氢渗透电流增大,且亚硫酸盐与镀层表面的缺陷协同效应进一步促进热浸镀钢材的氢吸收行为;氢吸收降低了热镀锌钢材的断后延伸率,表明海洋大气中的亚硫酸盐污染物会降低热镀锌钢材的韧性,导致氢损伤。 相似文献
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用Devnathan-Stachurski双电解池技术,对16Mn钢表面干湿循环时氢渗透现象进行了研究,结果表明不同表面液膜下,都有氢渗透电流的存在.氢离子渗透量与试样腐蚀失重之间存在线性关系.利用此线性关系制作的实时监测氢渗透电流的传感器,用以记录实际海洋大气中氢渗透电流,并根据氢离子渗透量与腐蚀失重之间的线性关系对海洋大气中钢材的腐蚀速率进行预测.结果表明,实际海洋大气中,氢渗透电流与环境湿度存在着对应关系,环境湿度由大变小时,氢渗透电流由小变大.环境湿度交替变化,在试样表面完成干湿循环,促进了氢的渗透,实际海洋大气与摸拟海洋大气失重取得了较好的一致性.可以用氢渗透电流传感器实时监测海洋用钢在大气中的氢渗透情况及腐蚀失重情况. 相似文献
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本文分析了气体通过迭层材料渗透的时间延迟,以设置阻挡层减小气体渗透为目标分析了阻挡层材料的真空特性及层数。设置布位对气体通过迭层材料渗透的动态影响,从而根据增大时间延迟而相对地减小气体渗透的原理提出了阻挡层合理布位的看法。 相似文献
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用射频磁控反应溅射法在Si(111)单晶基体上沉积ZrN扩散阻挡层,随后在其上分别用直流脉冲平衡磁控溅射(BMS)和非平衡磁控溅射(UBMS)沉积Cu膜.用XRD分析Cu膜的结构,AES分析薄膜成分,AFM观察沉积态Cu膜的表面形貌.结果表明,UBMS沉积的Cu膜可有效抑制Cu与Si基体之间的扩散,提高ZrN扩散阻挡层的热稳定性,UBMS沉积的Cu膜对扩散地抑制作用与其致密的结构有关. 相似文献
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表面氧污染的钛膜,其吸氢能力比清洁钛膜降低达数倍之多。在厚度d为40nm,表面氧污染的钛膜表面上,重新蒸镀一层极薄的(约1.2nm)清洁钛膜,吸氢、释氢的测量表明其吸氢能力得到恢复。另外,还对其他四块不同厚度的钛膜,在表面清洁及氧污染的条件下,分别进行了吸氢能力实验。实验结果证实:氧污染降低钛膜吸氢能力的原因是使钛膜上氢分子解离的位置减少,而不是扩散阻挡层的作用。 相似文献
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This paper presents the first results on the effect of nitrogen implantation on hydrogen permeation in steels. Nitrogen can modify superficially the steel's chemistry and/or microstructure depending on the fluence and thereby affect the processes of hydrogen diffusion and trapping. The implantations were performed on low carbon steel specimens with different nominal doses (1% to 10% and 33% nitrogen in a superficial layer of approximately 100 to 120 nm). The corresponding microstructures were characterized and permeation tests were conducted at room temperature in a double electrolytic cell. The nitrogen implanted layers on iron affects the electrochemical behaviour of the surface and the permeation in the material. This effect depends on the nitrogen concentration in the layer and on the corresponding microstructure. A continuous Fe2N layer acts as an efficient barrier to hydrogen entry and permeation when the layer is located on the entry face of the permeation membrane. This effect is stronger when the implanted layer is on the downstream face of the membrane. The low permeability values are mainly attributed to a lower hydrogen solubility in the implanted layer, whereas hydrogen trapping on defects and nitride precipitates delay hydrogen penetration. 相似文献
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Plasma-enhanced chemical deposition processes have been studied by comparing the performance of flexible diffusion barrier layers on plastic films produced in the same reactor. Under similar experimental conditions, a higher deposition rate is achieved by microwave discharges than by bipolar, pulsed d.c. magnetron sputtering processes. However, with both discharge modes, dense hydrocarbon coatings were produced, exhibiting a barrier improvement factor up to 120 and a flexibility ranging from 1.1%–8.8% before formation of microcracks started to dominate permeation characteristics. The density of the coatings is 1.0–1.6 g cm–3 and their hydrogen content varies from 23%–33%. 相似文献
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Passivation treatment for inhibition of hydrogen absorption in chromium-plated steel 总被引:1,自引:0,他引:1
Hydrogen permeation transients for passivated chromium-plated steels were measured at room temperature as a function of cathodic charging current density. The passivated film on chromium plating is shown to be an effective barrier to hydrogen at low cathodic charging current density (40 and 100 A cm–2). The passivated film can be reduced to chromium at higher cathodic charging current density (1 and 10 mA cm–2), promoting hydrogen absorption significantly. 相似文献
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热镀锌钢材在海洋大气环境中的氢渗透行为 总被引:1,自引:0,他引:1
用改进的Devanathan双面电解池在恒温、恒湿)条件下检测热镀锌钢材的渗氢电流密度并观测其腐蚀形貌,研究了温度对其氢渗透行为的影响.结果表明,在湿度相同的条件下,随着模拟海洋大气环境温度的升高试样的氢渗透加速,且湿度越高温度的这种加速作用越显著;在高温和高湿条件下,试样的氢吸收和氢渗透进行得更快. 相似文献
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Study of water behaviour of chemically treated flax fibres-based composites: A way to approach the hydric interface 总被引:1,自引:0,他引:1
Silane (Si) and styrene (S) treatments were applied on flax fibres in order to improve their adhesion with a polyester resin and to increase their moisture resistance. The water sorption and permeation kinetics of the composites were correlated with the water sorption behaviour of untreated and treated fibres. An increase of the water barrier effect was observed in treated fibres-based composites in comparison with untreated ones. This was related to the shift-down of water solubility and to a decrease of the water diffusivity in treated fibre-based composites. In the case of (S) treatment, the presence of styrene increased the moisture resistance of the treated fibres and made compatible the fibres and the matrix. In the case of (Si) treatment, a good hydric fibre/matrix interface was obtained due to crosslinking reactions and hydrogen bonding between water molecules and free hydroxyl groups of (Si) treated fibres. In order to interpret water permeation behaviour of composite films, a simple illustrated model is suggested and represented by a schematic view. 相似文献
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V. B. Kleshnya V. I. Sobornitskii N. N. Minagureeva N. G. Krapivnyi 《Materials Science》1995,30(1):57-60
We use the method of hydrogen permeation to study hydrogen permeation currents in 65GKh steel as functions of time under various polarization conditions. On the basis of experimental data, we find kinetic parameters of the interaction of hydrogen with defects (traps) in the metal. Experimental curves of hydrogen permeation currents are in good agreement with the theoretical curve plotted according to the general model of hydrogen trapping in the metal.Dnepropetrovsk Institute of Chemical Technology, Dnepropetrovsk. Translated from Fiziko-Khimicheskaya Mekhanika Materialov, Vol. 30, No. 1, pp. 61–64, January–February, 1994. 相似文献
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The principle, design, construction and performance of the amperometric and potentiometric sensors for measuring the permeation rate of hydrogen through the wall of metal equipment were investigated in order to develop a new type of hydrogen sensor with high accuracy. The transient curves of hydrogen permeation under a given charging condition were employed to evaluate the performance of two types of hydrogen sensors. The relative deviation of the hydrogen concentration detected with two types of sensors under the same condition varied from 3.0% to 13%. The accuracy, response time, reproducibility, and installation were discussed and compared. Response time of the potentiometric sensor (E-sensor) was shorter than that of the amperometric sensor (I-sensor). Both types of sensors exhibited good reproducibility. Development of I-sensor composed of a kind of proton conductor adhesives or non-fluid electrolytes which contain two functions of high electrical conductivity and a strong adhesion will be a promising prospect in order to measure hydrogen permeation at high temperature. 相似文献
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André Engesland Nataša Škalko-Basnet 《Drug development and industrial pharmacy》2016,42(11):1742-1751
Objectives: The phospholipid vesicle-based permeation assay (PVPA) is a recently established in vitro stratum corneum model to estimate the permeability of intact and healthy skin. The aim here was to further evolve this model to mimic the stratum corneum in a compromised skin barrier by reducing the barrier functions in a controlled manner. Methods: To mimic compromised skin barriers, PVPA barriers were prepared with explicitly defined reduced barrier function and compared with literature data from both human and animal skin with compromised barrier properties. Caffeine, diclofenac sodium, chloramphenicol and the hydrophilic marker calcein were tested to compare the PVPA models with established models. Results and discussions: The established PVPA models mimicking the stratum corneum in healthy skin showed good correlation with biological barriers by ranking drugs similar to those ranked by the pig ear skin model and were comparable to literature data on permeation through healthy human skin. The PVPA models provided reproducible and consistent results with a distinction between the barriers mimicking compromised and healthy skin. The trends in increasing drug permeation with an increasing degree of compromised barriers for the model drugs were similar to the literature data from other in vivo and in vitro models. Conclusions: The PVPA models have the potential to provide permeation predictions when investigating drugs or cosmeceuticals intended for various compromised skin conditions and can thus possibly reduce the time and cost of testing as well as the use of animal testing in the early development of drug candidates, drugs and cosmeceuticals. 相似文献