氢化燃烧合成Mg2NiH4产物高活性特征及分析

氢化燃烧合成法(HCS法)是镁基储氢合金制备的新方法,具有省能、省时、产物高活性等显著优点,近年来引起了国内外广泛关注.本文通过XRD、SEM和PCT等手段研究了氢化燃烧合成Mg2NiH4产物高活性的特征,并从物相组成、颗粒特性和氢化反应等方面揭示了HCS产物高活性的机理.结果表明,氢化燃烧合成Mg2NiH4产物在没有任何活化处理的前提下,第一次吸氢就能达到饱和吸氢量,且在不同温度下均具有比传统熔炼法产物Mg2Ni高的氢化活性;纯的物相组成、多孔的颗粒特性、大量微裂纹的存在和小的晶粒尺寸是其高活性的内在原因.本研究对控制HCS产物的微结构并进一步改善其储氢性能具有重要意义.

Characteristic and analysis of high activity of Mg2NiH4 produced by hydriding combustion synthesis

Hydriding combustion synthesis(HCS) has been widely recognized as an innovative processing to produce magnesium based hydrogen storage alloys in recent years.In this paper,the characteristic and mechanism of the high activity of Mg_2NiH_4 produced by HCS is discussed based on the analyses of phase composition,particle characteristic and hydriding reaction by means of x-ray diffraction(XRD),scanning electron microscopy(SEM) and pressure composition temperature(PCT).It is indicated that HCS product can reach the saturated hydrogen storage capacity in the first hydriding cycle without any activation process,and the hydriding activity is higher than that of IM product at various temperatures.Pure composition,loose and porous morphology,large number of micro-fissures and small crystal grain size are the intrinsic reasons of the high activity of Mg_2NiH_4 produced by the process of HCS.These results will be helpful to control and improve the hydrogen storage properties of HCS product based on the microstructure further.