摘要
The MgNi26 alloy was prepared by three different methods of gravity casting (GC), mechanical alloying (MA) and rapid solidification (RS). All samples were electrochemically hydrided in a 6 mol/L KOH solution at 80 °C for 240 min. The structures and phase compositions of the alloys were studied using optical microscopy and scanning electron microscopy, energy dispersive spectrometry and X-ray diffraction. A temperature-programmed desorption technique was used to measure the absorbed hydrogen and study the dehydriding process. The content of hydrogen absorbed by the MgNi26-MA (approximately 1.3%, mass fraction) was 30 times higher than that of the MgNi26-GC. The MgNi26-RS sample absorbed only 0.1% of hydrogen. The lowest temperature for hydrogen evolution was exhibited by the MgNi26-MA. Compared with pure commercial MgH2, the decomposition temperature was reduced by more than 200 °C. The favourable phase and structural composition of the MgNi26-MA sample were the reasons for the best hydriding and dehydriding properties.
采用重力铸造(GC)、机械合金化(MA)和快速凝固(RS)3种工艺制备MgNi26合金。将所有样品在浓度为6mol/L的KOH溶液中于80°C进行电化学氢化处理240min。采用光学显微镜、扫描电镜、能量分散光谱及X射线衍射技术研究合金的组织和相组成。利用程序控温技术分析吸氢和脱氢过程。机械合金化法制备的MgNi26-MA合金样品所吸附的氢含量(约1.3%,质量分数)比重力铸造法制备的MgNi26-GC合金样品所吸附的氢含量高30倍。快速凝固法制备的MgNi26-RS合金样品所吸附的氢含量仅为0.1%。MgNi26-MA合金显示出最低的析氢温度。与工业纯MgH2相比,MgNi26-MA合金的分解温度至少降低了200°C。MgNi26-MA合金优异的氢化和脱氢性能归因于其有利的相组成和组织结构。
基金
the Czech Science Foundation (project No. P108/12/G043) for the financial support of this research
作者简介
Corresponding author: V. KNOTEK; Tel: +420-220444055; Fax: +420-220444400; E-mail: Vitezslav.Knotek@vscht.cz
