摘要
在各种不同氢气储存方式中,用金属氢化物储存氢气具有体积小,压力低,安全性高等优点,其中A2B型的Mg2Ni介金属化合物具有高储氢量,质量轻,价格便宜等优点,而被视为最具潜力储氢系统.本实验采用(Mg2Ni)100-xAgxx(x=0,1.0及5.0)合金系统,进行机械合金法球磨处理,以X光衍射分析(XRD)检测技术观察粉体在球磨过程中结构变化,并将15h球磨处理后合金粉末进行储氢动力学曲线,压力-成分-温度曲线(P-C-Tcurve)与热分析等检测,对合金粉末储氢特性进行评估.结果发现15h球磨处理后,银元素会与Mg2Ni,Mg,Ni形成不同比例纳米晶粒混合物.在储氢特性方面,银元素的添加对Mg2Ni有明显改善,在350℃下,添加1.0%银元素与Mg2Ni粉体相比较,最大吸氢量由3.14%(ω)增加至3.83%(ω),可逆吸氢量由2.4%(ω)增加至3.0%(ω).
In many hydrogen storage methods,metal hydrides proposed to have some advantages such as greater volumetric efficiency,relatively low pressure,and high safety issue have attracted many R&D interests.Among a number of alloys,A2B type Mg2Ni intermetallic alloy due to its high hydrogen absorption capacity,lightweight and low cost is considered as a promising candidate for hydrogen storage applications.In the present study,an intermetallic powder with a desired composition of(Mg2Ni)100-xAgx(x=0,1.0 and 5.0) was directly prepared by mechanical alloying from pure Mg,Ni and Ag elemental powders under an inert gas.The structural transformations of as-milled powder mixtures in varied milling times were examined by X-ray diffraction(XRD) technique.The hydrogen storage kinetics,pressure-composition-temperature(P-C-T) curves and thermal analysis of 15 h milled Mg2Ni/Ag powders were evaluated.The experimental results showed that the 15 h as-milled powders were identified as a nanocrystalline mixture of Mg2Ni,Mg and Ni.Silver addition significantly improved the hydrogen absorption capacity of Mg2Ni,revealing that the absorbed hydrogen content and reversible hydrogen content at 350℃ were increased from 3.14 to 3.83%(ω) and from 2.40 to 3.0%(ω),respectively,for the 15 h milled Mg2Ni powder at silver content of 1.0%.
出处
《过程工程学报》
CAS
CSCD
北大核心
2006年第z2期258-262,共5页
The Chinese Journal of Process Engineering
