Sorption properties of Mg-Ni-CrCl3 hydrogen storage composite
(1.山东省威海市哈尔滨工业大学材料研究所2.School of Materials Science and Engineering, Harbin Institute of Technology, Harbin 150001, China3.Research Institute of Materials, Harbin Institute of Technology, Weihai 264209, China)
Abstract: Hydrogen absorption composite powder of Mg incorporated with Ni and CrCl3 （88∶10∶2 in mass ratio） was prepared by reactive milling in hydrogen atmosphere. Hydriding/dehydriding performances were measured by self-made apparatus. The results show that reactive milling and multi-component addition of Ni and CrCl3 reduce the stability of hydride and improve the sorption performance of Mg-based materials. With powder milled for 60h, hydriding basically completes within 300s （250℃, 2.0MPa） and phase transformation fraction reaches 0.78. The phase transformation rate of hydriding/dehydriding progress increases significantly with the reduced particles size of powder while good kinetics of dehydriding at a relatively low temperature is gained with small grain size of hydride. Rapid temperature variations in a short span of time resulted from remarkable calorific effects of rapid phase transformation are detected in hydriding/dehydriding progress. The results of thermogravimetric and differential scanning calorimetric（TG/DSC） indicate that the onset temperature of desorption of composite milled for 100h is 272℃.
Key words: Mg-Ni-CrCl3 composite； hydrogen storage materials； reactive milling； multi components addition； stability； calorific effects