利用D-D核反应研究氘在钯中的沉积行为

发布时间：2018-05-30 03:27

本文选题：钯 + D-D核反应　；参考：《兰州大学》2017年硕士论文

【摘要】：钯(Pd)是一种非常重要的储氢材料,具有较强的吸氢能力。钯在氢同位素的分离过程中也起着非常重要的作用,它能够制成透过膜用于氢与杂质的分离以获得高纯度的氢。钯还可以在储氢材料的制备中作为氢化催化剂来提升其储氢性能。因此,需要对氢同位素与钯的相互作用,如氢、氘在钯中的沉积行为(扩散、吸附/解析附,表面复合等)进行研究。本工作将氘离子束注入钯中,并利用氘离子诱发D-D核反应的方法研究了氘在钯中的动态和静态浓度。实验首先将能量为14-20 ke V/D的D+3强束注入钯箔,同时监测出射质子产额,当产额不随注量发生变化时即认为靶内氘浓度达到饱和,通过质子产额即可获得靶内动态氘浓度;在每一次注入之后停束一段时间,利用能量为75 ke V/D的D+弱束诱发的D-D核反应监测停束后钯靶中的静态氘浓度。进一步,根据氘在钯靶中的扩散、吸附/解吸附、表面复合等行为建立了理论模型,其中动态氘浓度由注入达到饱和后的自由扩散态氘浓度CD、非稳定束缚态氘浓度CA以及稳定束缚态氘浓度CT组成,且静态氘浓度为稳定束缚态氘浓度CT。通过该模型计算了在各注入能量下钯靶中三种类型的氘浓度的深度分布及其时间演化。结果表明:(1)钯靶中稳定束缚态氘浓度(CT)存在饱和值(2.9±0.2)×1020/cm3,其原子密度之比nD/nPd为(0.42±0.03)at.%。(2)注量~1017/cm2后,钯靶中自由扩散态氘浓度(CD)及非稳定束缚态氘浓度(CA)达到动态平衡,CD/CA约为1/600。当停束后,该部分氘迅速减少直至消失。(3)本实验中,根据模拟计算得到吸附系数(kA)和解吸附系数(kD)分别为39 s-1和6×10-2 s-1。本工作利用D-D核反应分析法对自吸收钯靶中的氘浓度进行了实时分析,所建模型能较好地符合实验结果,该方法可用于其它材料中氘沉积的实时分析。
[Abstract]:Palladium palladium (PD) is a very important hydrogen storage material with strong hydrogen absorption ability. Palladium also plays an important role in the separation of hydrogen isotopes. Palladium can be used to separate hydrogen from impurities through membranes to obtain high purity hydrogen. Palladium can also be used as hydrogenation catalyst in the preparation of hydrogen storage materials. Therefore, the interaction of hydrogen isotopes with palladium, such as the deposition behavior of hydrogen and deuterium in palladium (diffusion, adsorption / desorption, surface recombination, etc.) needs to be studied. In this work, deuterium ion beam was implanted into palladium, and the dynamic and static concentrations of deuterium in palladium were studied by D-D nuclear reaction induced by deuterium ion. Firstly, the D 3 strong beam with energy of 14-20 Kev / D was injected into the palladium foil, and the proton yield was monitored. When the yield did not change with the flux, the deuterium concentration in the target reached saturation and the dynamic deuterium concentration in the target could be obtained by the proton yield. The D-D nuclear reaction induced by D weak beam with 75 ke V / D energy was used to monitor the static deuterium concentration in the PD target after each injection for a period of time. Furthermore, a theoretical model of deuterium diffusion, adsorption / desorption, and surface recombination in palladium target was established. The dynamic deuterium concentration is composed of the free diffusion deuterium concentration (CD), the unsteady bound state deuterium concentration (CA) and the stable bound state deuterium concentration (CT), and the static deuterium concentration is the stable bound state deuterium concentration (CTT). The depth distribution and time evolution of three types of deuterium concentrations in the palladium target at various implanted energies were calculated by the model. The results show that the stable bound deuterium concentration in the palladium target has a saturation value of 2. 9 卤0. 2) 脳 10 ~ 20 / cm ~ (3), and the atomic density ratio (nD/nPd) is 0. 42 卤0. 03 at. 2) after the flux of 1017 / cm ~ 2, the free diffusion state deuterium concentration in the palladium target and the unsteady bound state deuterium concentration can reach a dynamic equilibrium of about 1 / 600. When the beam was stopped, the deuterium decreased rapidly until it disappeared.) in this experiment, the adsorption coefficient K A) and the desorption coefficient K D were 39 s -1 and 6 脳 10 -2 s -1, respectively. In this work, the deuterium concentration in self-absorbed palladium target is analyzed in real time by D-D nuclear reaction analysis. The model can be used for the real-time analysis of deuterium deposition in other materials.
【学位授予单位】：兰州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TG146.36;O613.2

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