直流法测量钯氢化物电极电阻时的阻值偏移

讨论了直流法在线测量钯氢化物电极电阻时的电化学效应，计算了电解液的共导、测量电流与电解电流引起的浓差电池效应以及电极作为集流体引起的电阻贡献。结果表明：当电极具有高的长度与半径比值、粗糙的表面、高的溶液电导以及大的电解电流时容易引起显著的附加电阻。     

钯与氢(H2,D2)反应的热力学性质研究

采用PVT方法精确测定了 40～ 60目的海绵钯 (Pd)粉末在 5～ 5 0℃范围内吸放H2 ,D2 的P C T曲线。结果表明 :2 5℃ ,0 .1MPa时H2 ,D2 在Pd中的溶解度分别为 75 .8和 70 .4ml(STP)·g- 1 Pd;Pd与H2 ,D2 反应的坪台热力学函数分别为 :ΔHa=-18.7kJ·mol- 1 H ,-17.6kJ·mol- 1 D ,ΔSa=-4 6.4J·K- 1 ·mol- 1 H ,-4 9.6J·K- 1 ·mol- 1 D ;ΔHd=2 1.3kJ·mol- 1 H ,18.7kJ·mol- 1 D ,ΔSd=5 0 .8J·K- 1 ·mol- 1 H ,49.1J·K- 1 ·mol- 1 D。H ,D在α相的溶解热力学函数为 :ΔHr→ 0 =-6.5kJ·mol- 1 H ,-5 .6kJ·mol- 1 D ;ΔSr→ 0 =-5 3 .5J·K- 1 ·mol- 1 H ,-5 3 .7J·K- 1 ·mol- 1 D。Pd Q(Q =H ,D)体系存在明显的迟滞效应 ,升高温度可改善吸放氢循环的压力迟滞效应 ,但不能消除。伴随迟滞效应的吉布斯自由能损失 (ΔGloss)在低于 5 0℃时保持不变 ,对Pd H和Pd D体系分别为 1.2 8和 1.2 5kJ·mol- 1 H(D) ;当高于 5 0℃时ΔGloss分别减小约 4%和 11%。     

载钯硅藻土制备及吸/放氢性能分析

采用(NH4)2Pd(NO3)4浸渍-热分解法制备了钯含量为44.5%±0.1%的载钯硅藻土(Pd/K)颗粒,对材料进行了BET、XRD、X荧光、冷热循环分析,测定了常温下的吸/放氢(氘)等温线。结果表明,Pd/K经多次吸/放循环后有轻微的粉化;随循环次数的增加,粒径分布趋于稳定。与纯钯相比,吸/放氢(氘)等温线呈现坪台压力上升,坪斜增加,吸氢容量减小的特点;同一温度下,氕的滞后效应明显大于氘;温度升高,滞后效应减小。     

钯柱内氢同位素排代计算机模拟

利用气-固相氢同位素交换模型，对钯柱上的氢同位素排代进行了计算机模拟。计算了氕排代氘、氘排代氕以及氘排代氚过程中钯柱流出端氢同位素各组分丰度随流入气量的变化关系，研究了氢同位素分离因数、比表面积以及排代柱长度对排代效果的影响。结果表明：根据数学模型获得的排代流出曲线与实验结果具有很好的一致性；增大材料的比表面积，可以显著地改善排代效果；对于具有正氢同位素效应的金属．氢体系，排代效果与分离因数关系密切：分离因数越大，排代效果越好；氘排代氕以及氘排代氚的效果均不如氕排代氘；在所涉及的范围内，当体积流速恒定，排代柱的长度对排代效果没有影响。     

钯氢化物同位素分离因子的理论计算与实验测定

根据理想溶液模型计算了PdHxDy的解吸等温线和氕氘分离因子(α)，实验研究了α与氢钯比(r)、温度(T)和固相氕(H)的原子摩尔分数(xH)的关系，并将理论计算与实验结果及文献数据进行了比较分析。结果表明，Pd-(H D)体系的离解压随xH增加呈现出类似双曲线的单调非线性减小；在坪台区时，离解压与总的氢钯比(r)无关；当r≥0．6时，离解压随xH增加而减小的趋势更为明显。PdHxDy的分离因子的计算值随xH增加而减小的趋势不及实验结果明显，当xH越大，α减小越明显；xH相同时，坪台区的α与r无关，但β相(r≥0．6)的α随r的增加而增加。分离因子随着温度升高以指数函数下降。当xH→0和xH→1时，α的计算值分别为2．6和2．1，与实验值一致。     

钯合金膜分离器级串氢同位素分离

基于钯合金膜分离系数测定的实验结果,设计了单级钯合金膜氢同位素分离器,测试了分离器对H-D混合气体的分离系数,建立了该分离器在理想级串下达到一定分离要求所需的分离级数和分离膜面积,以及分离过程中氢同位素丰度变化的计算模型。结果表明,在673K,分流比为0.1时,该分离器对54.3%H2-45.7?的分离系数为1.54;单级分离器的分离系数是级串分离系统级数的决定性指标,提高单级分离器的分离系数可以减少分离系统的级数,提高分离系统的效率。     

钯及钯合金镀层的应用

较详细地介绍了钯及钯合金镀层的镀液组成、工艺条件及其应用领域。以钯及钯合金镀层代替金镀层将成为电子工业今后的发展方向，其在装饰业亦有可能取代铑、铂镀层。     

稀土元素在钯基氢净化材料上的应用

根据近年来钯基氢净化材料的研究状况,综述了添加稀土元素对钯基氢净化材料的影响。重点从稀土元素对钯吸氢后形成α相向β相的转变、透氢性能、力学性能以及有害杂质污染的抵抗能力等4个方面进行了阐述。说明添加稀土元素,特别是Y可明显改善钯膜的性能,为低廉、高效获得高纯氢提供了良好的途径。     

稀土的重要潜在市场—稀土贮氢材料

本文介绍了稀土贮氢材料的性能、制备和应用,指出稀土贮氢材料是稀土特别是轻稀土的重潜在市场。     

关于金属材料理化特性化工设备节能工艺的探讨

现如今,经济和科技在不断进步,化工行业也在迅速发展。但在化工行业发展的过程中,能源问题日益加剧。为了缓解能源问题,促进我国的可持续发展,要积极研究化工设备节能工艺。为了降低能源的消耗,可以从金属材料理化特性入手,改善化工设备节能工艺,提升设备节能效果,本文就此进行了相关的阐述和分析。     

Study on Physical and Chemical Behaviors of Rare Earths in Preparing Ceramic Tube Supported Palladium Film by Electroless Plating

The rare earths of ytterbium, lanthanum, praseodymium, neodymium and their binary mixtures were respectively added into the traditional electroless plating solution to prepare thin palladium film on the inner surface of porous ceramic tube. The experimental results shows that the addition of rare earths increases palladium deposition rates and the binary mixtures are superior to the single rare earths and the mixture of ytterbium-lanthanum is the most efficient. Adding the mixture of ytterbium-lanthanum can also reduce the plating temperature by 10～20 ℃, shrink the metal crystal size and improve the film densification compared to those by traditional electroless plating. A thin palladium film with 5 μm was prepared and the film made a highly pure hydrogen with a molar fraction of more than 99.97% from a H2-N2 gas mixture. More attentions were paid to analyze the physical and chemical behaviors of the rare earths in palladium film preparation.     

燃料电池用金属氢化物贮氢罐的研究

金属氢化物贮氢罐是燃料电池的侯选氢源之一 ,由于其安全性好、体积贮氢密度高、提供的氢气纯度高 ,因此在小型燃料电池及某些特定环境 (如潜艇、电动铲车 )的应用中具有极强的竞争力。北京有色金属研究总院研制开发出可分别与 3kW ,2 0 0W及 30W燃料电池配套的多种类型贮氢罐 ,成功地应用在电动摩托车、电动自行车和手机上     

热处理对快淬贮氢合金组织和电化学性能的影响

通过XRD、SEM分析和电化学实验,研究了热处理对快淬贮氢合金组织和电化学性能的影响。研究表明,400℃热处理对快淬合金晶粒变化不明显,900℃热处理后合金晶粒明显长大,1100℃热处理使合金部分熔化,随后发生了平衡凝固;900℃热处理后,单胞体积和放电容量均达到最大值,但充放电循环稳定性最差,400℃和1100℃热处理后,放电容量稍有降低,但充放电循环稳定性较好。     

Consistency Research of Negative Electrode Pasting for MH/Ni High Power Battery

It is discovered that the consistency of negative electrode is one of the main influences on battery performance, since the main raw material in negative electrode is metal hydride powder, ingredients, particle distribution and density of the powder could influence the pasting consistency in some aspects.With the study of MH powder characteristics, through the modification of the coating die, the consistency of negative electrode is improved efficiently.     

Influence of elemental composition on crystal structure and hydrogen storage performance for Mg-containing alloys

The influence of elemental composition on the crystal structure, hydrogen storage and electrochemical properties for Mg-containing alloys was investigated. As La/Mg ratio decreased, the slight change of Ni content was detected. XRD results indicated that these alloys were composed of LaNi 5 and Mg-containing phases. The lattice parameters of Mg-containing phases decreased. Meanwhile, the mass fraction of Mg-containing phases varied with the change of La/Mg and Ni. The hydrogen storage capacity reached ～1.6 wt.% for La/Mg≧ 3 :1 and decreased to ～0.71 wt.% for La/Mg=1. Two hydrogen absorption processes were observed because of the existence of the multiphases for La/Mg≧ 3 :1. With decreasing La/Mg ratio, the equilibrium pressurerose due to the shrinkage of the lattice parameter. Meanwhile, one hydrogen absorption process was obviously present. The discharge capacity of these as-cast alloys was higher, but the cyclic stability was poor for La/Mg≧ 3 :1 due to the partial amorphisation. It was better for La/Mg≤2 although the discharge capacity was lower. The polarization resistance increased, contrarily the exchange current density decreased with decreasing Mg content.