【作者】 唐体春；

【导师】 陈玉安；

【作者基本信息】 重庆大学 ， 材料科学与工程， 2007， 硕士

【摘要】 镁基储氢材料由于其储氢量高、密度小、资源丰富与价格低廉等一系列优点,因此被一致认为是最有开发前景的储氢材料之一。然而它也存在着吸放氢条件比较苛刻,生成的氢化物过于稳定,吸氢动力学性能差,合金循环寿命低等缺点。本文通过两步法(球磨+烧结)制备出Mg2Ni、Mg-Al-Ni与Mg-Ni-Cu三个系列5种储氢合金,通过机械合金化法制备出Mg2Ni、Mg-Al-Ni、Mg-Ni-Cu三个系列6种储氢合金。并对所制备的合金进行了X射线结构分析、SEM分析、粒度分析、电化学性能分析和储氢性能分析(包括吸氢速率分析、吸氢和放氢PCT曲线分析),实验结果表明:①采用两步法可以制备出Mg2Ni、Mg-Al-Ni、Mg-Ni-Cu三个系列5种合金。X射线结构分析表明,两步法制备出来的所有合金的主相均为Mg2Ni相,在Mg-Al-Ni系列合金中出现了另一种吸氢相Mg3AlNi2,同时在Mg-Ni-Cu系列合金中出现了吸氢相Mg2Cu。气态储氢性能分析结果表明,在这三个系列合金中,Mg2Ni合金在400℃时的最大储氢量达到了2.52wt%,但是其循环稳定性比较差。元素Al和Cu的加入能够明显地改善合金的放氢率和循环稳定性,其放氢率达到了70%左右。②采用机械合金化法可以在室温下制备出Mg2Ni、Mg-Al-Ni、Mg-Ni-Cu三个系列6种合金。X射线结构分析表明,6种合金的主相均为Mg2Ni相。在Mg-Al -Ni系列合金中出现了另一种吸氢相Mg3AlNi2,同时在Mg-Ni-Cu系列合金中出现了新相Cu11Mg10Ni9。气态储氢性能分析结果表明,通过机械合金化法可以使合金在较低的温度下就可以吸放氢,Mg2Ni合金在350℃时的最大储氢量达到了3.41wt%,但是其放氢率比较低。元素Al和Cu的加入使得吸氢平台有所上升,但是低温放氢性能得到很大的改善。另外,本文还着重讨论了制备工艺参数与吸氢相Mg3AlNi2对合金储氢性能的改善机理。更多还原

【Abstract】 The problems of environment and energy sources were regarded at present, therefore, the hydrogen energy was favored by the scientists all over the world because of its cleanness. As the storage and transportation medium of hydrogen, the hydrogen storage materials research became a very pop item. For the great hydrogen storage capacity, low density and inexpensive value, the Mg-based hydrogen storage materials were thought as the most promising one, but its thermodynamics and kinetics properties in hydrogen absorbing process were worse and it’s antierodibility in lye was bad too. In this study, three kinds of Mg based hydrogen storage (Mg2Ni, Mg-Al-Ni series and Mg-Ni-Cu series) were prepared by two step method (engine activation and sinter in solid), and three kinds of alloys (Mg2Ni, Mg-Al-Ni and Mg-Ni-Cu series) were synthesized by mechanical alloying. After that, XRD, SEM, microstructure, granularity, electrochemistry properties and hydrogenation properties (including the absorption velocity curve, absorption and desorption PCT curves of samples) analysis were employed, the results showed that:①5 kinds of alloys (Mg2Ni, Mg-Al-Ni series、Mg-Ni-Cu series) can be synthesized by two step method. XRD results showed that all the alloys’main phase was Mg2Ni, and the other hydrogen storage phase (Mg3AlNi2) was also found in Mg-Al-Ni alloys, at the same time the hydrogen storage phase (Mg2Cu) was also found in Mg-Ni-Cu alloys. The hydrogen storage analysis indicated that the Mg2Ni alloys’hydrogen storage properties was 2.52wt% at 400℃. Its cycle stabilities were bad. The analysis showed that the substitution of Mg by Al and the substitution of Ni by Cu can improve the alloys’cycle stabilities properties. The desorption ratio was increased to 70%.②6 kinds of alloys (Mg2Ni, Mg-Al-Ni series、Mg-Ni-Cu series) can be produced by mechanical alloying. XRD results showed that the six kinds of alloys’main phase were Mg2Ni, and the other hydrogen storage phase (Mg3AlNi2) was also found in Mg-Al-Ni alloys, at the same time the hydrogen storage phase (Cu11Mg10Ni9) was also found in Mg-Ni-Cu alloys. The hydrogen storage analysis showed that the alloys produced by mechanical alloying can absorb hydrogen at lower temperature. The Mg2Ni alloys’hydrogen storage properties was 3.41wt% at 350℃, but it’s desorption ratio was bad. The analysis showed that the substitution of Mg by Al and the substitution of Ni by Cu can improve the alloys’absorption plateau and desorption properties at low temperature.In the end, the manufacturing technology parameters and hydrogen storage phase Mg3AlNi2 relation between hydrogenation was discussed.更多还原