贮氢材料的研究和发展

本文论述了贮氢材料工作原理,氢化物形成热力学和动力学问题,总结了目前三大系列,15种适用的贮氢合金的成分,性能和 P-T-C 曲线。文章介绍了贮氢材料在贮氢、输送氢,氢气纯化,热泵,空调,氢压缩机,燃氢汽车等方面的多种用途。本文不仅概括了许多最新资料,而且总结了作者多年来从事贮氢材料研究的经验和体会。     

碳中和背景下氢能利用关键技术及发展现状

氢能作为一种二次能源,因其绿色、灵活、来源广泛等特点,将在可再生能源占主导的未来能源体系中发挥重要作用。决定氢能产业大规模发展的核心是实现低廉、高效的原料来源和储运。为此,从可再生能源电解水制氢和储氢运输2个方面,对实现氢能清洁和高效利用的关键技术进行了综述。总结了欧洲和日本作为氢能利用的领先国家在氢能发展方面的一些思路与进展,也对氢能的成本因素进行了讨论。分析了我国氢能发展的趋势,对于未来我国氢能产业发展的前景,提出以下建议:建立健全法规与政策体系;重视氢源供应及储运的发展;积极探索发展各类氢能利用方式。     

高容量储氢材料的研究进展

氢能是一种理想的二次能源.氢能开发和利用需要解决氢的制取、储存和利用3个问题,而氢的规模储运是现阶段氢能应用的瓶颈.氢的储存方法有高压气态储存、低温液态储存和固态储存等3种.固态储氢材料储氢是通过化学反应或物理吸附将氢气储存于固态材料中,其能量密度高且安全性好,被认为是最有发展前景的一种氖气储存方式.由轻元素构成的轻质高容量储氢材料,如硼氢化物、铝氢化物、氨摹氢化物等,理论储氢容量均达到5%(质量分数)以上,这为固态储氢材料与技术的突破带来了希望.新型储氢材料未来研究的重点将集中于高储氢容量、近室温操作、可控吸/放氢、长寿命的轻金属基氢化物材料与体系.     

Influence of activation energy and sensitivity to hydrogen embrittlement on fatigue strength degradation by irreversible hydrogen in high‐strength steels

Fatigue tests were conducted for cold‐drawn eutectoid steels having different activation energies for irreversible hydrogen trap sites and sensitivities to hydrogen embrittlement; the purpose was to investigate the mechanism of fatigue strength degradation by irreversible hydrogen. The fatigue strength of a sample with low activation energy was decreased by irreversible hydrogen in the material, whereas the fatigue strength of a sample with high activation energy was not. When the activation energies for irreversible hydrogen were almost equal, a higher sensitivity to hydrogen embrittlement induced fatigue strength degradation by irreversible hydrogen. Therefore, fatigue strength degradation by irreversible hydrogen depends on the activation energy for irreversible hydrogen trap sites and sensitivity to hydrogen embrittlement.     

Hydrogen in metals

The effects of hydrogen on various metals and the use of metal hydrides for hydrogen storage are discussed. The mechanisms of, and differences between, hydrogen embrittlement and hydrogen attack of ferritic steels are compared, common sources of hydrogen in metals processing and treatment identified, and mechanisms for hydrogen entry into a ferritic surface are discussed. The differences between hydrogen attack of ferritic steels and copper alloys are contrasted, and an unusual case study of hydrogen embrittlement of an alloy steel is presented.     

Hydrogen induced catalysis by silver-exchanged zeolites: transformation of ethylbenzene over AgY zeolite

Catalytic activity of AgY at 473 K is greatly enhanced by the presence of hydrogen. Activity in the presence of hydrogen is much higher than that observed for HY, where the presence of hydrogen has no effect. The effect caused by hydrogen is reversible. When hydrogen is removed from the system, activity decreases. Activity is restored by the re-introduction of hydrogen into the system. This shows that hydrogen is reversibly chemisorbed to form protons in the zeolite. It is suggested that the interconversion of hydrogen molecules and protons is related to the redox property of the small silver clusters.     

PEMFC备用氢能发电站的储氢问题探讨

在介绍目前国内外各种成熟的工业储氢方法,并指出储氢技术研究热点和发展方向的基础上,针对人防工程备用氢能发电站的技术要求,对各种适用的储氢方式进行了比较,探讨了人防工程备用氢能发电站的氢气储存方法,以及氢气安全储存、运输与监控、反应热处理等问题。     

氢在钢中晶格间隙和氢陷阱之间的扩散模式

氢在晶格间隙和陷阱点的扩散包括：氢在晶格间隙之间的扩散,氢从晶格间隙扩散到陷阱点,氢从陷阱点逃逸到晶格间隙的过程。本文运用气体在金属中的扩散理论,分析了氢在钢中晶格间隙和氢陷阱之间的扩散模式,以及通过扩散在两者之间建立的平衡状态。氢陷阱中氢浓度随时间的变化率等于晶格间隙的氢扩散到陷阱点引起的氢浓度变化率减去陷阱点中氢逃逸到晶格间隙引起的氢浓度变化率,其数学关系式符合McNabb和Foster建立的氢陷阱模型。氢在晶格间隙和陷阱点之间的平衡,实质是氢在晶格间隙的化学势μL和氢在陷阱点的化学势μT之间达到局部平衡,氢在陷阱中的占据分数很低的情况下（θT《1）,氢的有效扩散系数Deff的表达式是与陷阱结合能EB有关的温度函数。     

Effect of substrate on hydrogen in and out diffusion from a-Si:H thin films

We present a detailed study on the effect of the substrate on the structure and hydrogen evolution from p-type hydrogenated amorphous silicon thin films co-deposited on the grounded and RF electrodes of an asymmetric radio frequency glow discharge reactor, as well as the similar films exposed to an hydrogen plasma. We used spectroscopic ellipsometry and hydrogen evolution measurements to analyze the effects of the substrate, ion energy and hydrogen plasma on the films microstructure, thickness, hydrogen content, hydrogen binding and hydrogen evolution. The hydrogen evolution spectra show a strong substrate dependence. In particular on crystalline silicon substrate, we observe the formation of bubbles. For the various substrates, ion energy and hydrogen plasma treatment do not affect the hydrogen evolution spectra. These results indicate that the action of hydrogen in a-Si:H is modified by the nature of the substrate.     

TBAC水合物粉储存氢气实验研究

采用激光拉曼光谱法对初始压力9 MPa,初始温度273 K,TBAC浓度3%的条件下,四丁基溴化铵(TBAC)水合物粉与氢气生成的TBAC-H2水合物进行了研究,探讨了氢气在TBAC水合物中对笼的占据情况,计算了其储氢密度,并与相同条件下TBAC水溶液的储氢方法做了比较。结果表明:在TBAC水合物中,氢气只填充在水合物的小笼中。在上述条件下,TBAC水合物粉的储氢密度为0.1%,TBAC水溶液的储氢密度为0.021%,采用TBAC水合物粉储存氢气可以提高水合物的储氢密度,这是因为TBAC水合物粉能够增大边界层的接触面积,从而有利于水合物形成过程中的传质,增加水合物的生成量。     

Diffusion of Hydrogen along the Grain Boundaries in Ni3Al Alloys

The diffusivity of hydrogen in two Ni3Al alloys (No.1 and No.2) has been measured in the temperature range of 100℃ to 420℃ using an ultrahigh vacuum gaseous permeation technique. The diffusivity data fall into two segments, in which the hydrogen diffusivity adheres to the Arrhenius form, respectively. From the hydrogen diffusivity, it is conjectured that the hydrogen diffusivity reflects the hydrogen transportation along the grain boundaries at lower temperature and the hydrogen transportation in the lattice at higher temperature. The intergranular fracture of Lit-type intermetallics induced by hydrogen at relative low temperature results from hydrogen transportation along the grain boundaries and not in the lattice.     

In vivo imaging of hydrogen peroxide with chemiluminescent nanoparticles

The overproduction of hydrogen peroxide is implicated in the development of numerous diseases and there is currently great interest in developing contrast agents that can image hydrogen peroxide in vivo. In this report, we demonstrate that nanoparticles formulated from peroxalate esters and fluorescent dyes can image hydrogen peroxide in vivo with high specificity and sensitivity. The peroxalate nanoparticles image hydrogen peroxide by undergoing a three-component chemiluminescent reaction between hydrogen peroxide, peroxalate esters and fluorescent dyes. The peroxalate nanoparticles have several attractive properties for in vivo imaging, such as tunable wavelength emission (460-630 nm), nanomolar sensitivity for hydrogen peroxide and excellent specificity for hydrogen peroxide over other reactive oxygen species. The peroxalate nanoparticles were capable of imaging hydrogen peroxide in the peritoneal cavity of mice during a lipopolysaccharide-induced inflammatory response. We anticipate numerous applications of peroxalate nanoparticles for in vivo imaging of hydrogen peroxide, given their high specificity and sensitivity and deep-tissue-imaging capability.     

Molecular hydrogen pressure in macrocollectors during hydrogen charging of steel at elevated temperatures

When a metal is being charged with hydrogen by exposing it to omnidirectional pressure of a hydrogen-bearing medium, the molecular hydrogen pressure in macrocollectors reaches the partial hydrogen pressure in the medium. In the case of metals exposed to unidirectional pressure of a hydrogen-bearing medium, the hydrogen pressure in collectors situated near the absorbing surface reaches the level of the partial hydrogen pressure in the medium and approaches zero in collectors situated near the desorbing surface. An inert (in respect to hydrogen) gas present in a collector under pressure does not inhibit the accumulation of hydrogen in this collector.     

再谈氯碱氢深度脱水工艺

概述了氢气的主要生产方法、实际应用以及氯碱工业近年来的产能情况。详细介绍了氯碱氢的深度脱水工艺流程,并结合氯碱氢深度脱水装置的调试情况,对氯碱氢的脱水原理、氯碱氢深度脱水装置脱水效果的最佳工况选择做了进一步的研究。     

Evaluation of automobile service performance using laboratory testing

A methodology is presented to evaluate martensitic advanced high-strength steels in auto service. There was essentially no influence of hydrogen for (i) linearly increasing stress tests of specimens with hydrogen contents much greater than for automobile service, and (ii) for tensile tests with simultaneous hydrogen charging and with a substantial hydrogen content. These results allow evaluation of the hydrogen influence for the tested steels for auto service. In contrast, electrochemically hydrogen charged martensitic advanced high-strength steels showed an influence of hydrogen on mechanical properties, manifest as (i) a decrease in yield strength, by hydrogen enhanced macroscopic ductility, and (ii) a change of the micro-fracture mode, by hydrogen-assisted micro-fracture.     

粉末冶金企业氢气系统设计的经济性及安全性分析

从制氢工艺的选取、制氢系统规模确定及制氢设备的选择三个方面对粉末冶金企业的氢气系统设计的经济性进行分析,并在分析中提出了一些经济指标的经验数据。同时从避免氢、氧混合爆炸性气体形成及消除引火能源这两方面对氢气系统设计的安全性进行分析,并提出设防措施。     

有序度对Ni2Cr合金氢致脆断的影响

研究了环境气氛、动态渗氢及预渗氢对不同有序度Ni2Cr合金脆化的影响.结果表明,有序度对Ni2Cr合金在室温空气及氢气中的环境氢脆没有明显影响;动态渗氢拉伸时Ni2Cr合金存在严重的氢脆敏感性,无序和高度有序合金比部分有序合金脆化严重;预渗氢时,氢原子通过晶格扩散及晶界扩散进入合金,Ni2Cr合金氢脆敏感性随有序度的增大而减小.     

Hydrogen hardening effect in heavily deformed single crystal α-Fe

Molecular dynamics simulations were performed to investigate the hydrogen interaction with edge dislocations during deformation in α-Fe. In particular, uniaxial tensile tests of a single crystal iron were conducted after the single crystal was plastically deformed to introduce high density of edge dislocations and was doped with different levels of lattice hydrogen concentration. During system relaxation, hydrogen atoms have tendency to diffuse and stay around dislocation line – a well-known hydrogen trap-site in α-Fe. Our simulations show that the yield strength of the bcc iron is very sensitive to the presence of hydrogen within edge dislocations, i.e., it increases as hydrogen concentration increases. After yielding, hydrogen atoms are de-associated with the moving dislocations, suggesting that the yield strength enhancement is caused by the hydrogen pinning effect. This direct observation of hydrogen hardening effects has confirmed the experimental findings by Matsui, etc. Additional simulations also indicate that hydrogen interaction with edge dislocations is sensitive to temperature as well as vacancies around dislocation core.     

THE EFFECT OF HYDROGEN ON FATIGUE AND DISLOCATION BEHAVIOR OF AN α/β TITANIUM ALLOY

Abstract— Fatigue thresholds and crack growth rates were studied in the experimental alloy, Ti—5Al—4Mo, as a function of temperature, grain size and hydrogen concentration. Deformation is confined to planar slip bands along which fracture occurred at low hydrogen concentrations. Hydrogen accelerated crack growth rates at various combinations of temperature, grain size and hydrogen with a corresponding change in fracture from "cleavage' to interface phase fracture. In addition, hydrogen was found to promote interface phase formation. It is proposed that stress-assisted hydrogen accumulation increases the interface phase hydrogen concentration which reduces the interface phase fracture stress. This process depends on the local stress and β -phase hydrogen concentrations, temperature and the time under load. At 340 K, hydrogen had a relatively small effect on crack growth due to a change in slip behavior with increased hydrogen concentration.     

氢动力车用液氢贮罐的发展现状及展望

综述了随车贮氢技术的发展过程和现状,比较了各种随车贮氢技术的特点,认为液氢贮氢具有重量轻、体积小、安全、加注时间短等突出优点,是氢动力车的首选贮氢方式。介绍了随车液氢贮罐以及液氢充装系统的技术特点,分析了我国目前液氢贮罐的制造能力、技术现状以及今后的发展方向。