Dehydriding reaction kinetic mechanism of MgH_2-Nb_2O_5 by Chou model  

作　　者：刘杨 李谦 周国治 

机构地区：[1]Shanghai Key Laboratory of Modern Metallurgy and Materials Processing,Shanghai University [2]School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing

出　　处：《中国有色金属学会会刊：英文版》2008年第A01期235-241,共7页Transactions of Nonferrous Metals Society of China

基　　金：Project(2006AZ001)supported by the Shanghai Municipal Education Commission,China;Project(06JC14031)supported by the Scienceand Technology Commission of Shanghai Municipality,China;Project(06QA14021)supported by the Shanghai Rising-Star Program(Atype),China;Project(200746)supported by the Foundation for the Author of National Excellent Doctoral Dissertation of China;Projectsupported by the Innovation Fund for Graduate Student of Shanghai University,China

摘　　要：Chou model was used to investigate the dehydriding reaction kinetic mechanism of MgH_2-Nb_2O_5 hydrogen storage materials at 573 K.A new conception,'characteristic absorption/desorption time(t_c)'was introduced to characterize the reaction rate The fitting results show that for the hydrogen desorbing mechanism,the surface penetration is the rate-controlling step.The mechanism remains the same even when the original panicle size of Nb_2O_5 is before ball milling(BM) or when the BM time changes And t_c indicates that the desorption rate of MgH_2-Nb_2O_5 will be faster than that of MgH_2-Nb_2O_5 by BM.The dehydriding reaction rate of MgH_2-Nb_2O_5(micro particle) BMed for 50 h is 4.76 times faster than that of the MgH_2-Nb_2O_5(micro panicle) BMed for 0.25 h,while the dehydriding reaction rate of MgH_2-Nb_2O_5(nano particle) BMed for 50 h is only 1.18 times as that of the MgH2-Nb_2O_5 (nano particle) BMed for 0.25 h.The dehydriding reaction rate of the BMed MgH_2-Nb_2O_5(nano particle) is 1-9 times faster than that of the BMed MgH_2-Nb_2O_5(micro particle).Chou model was used to investigate the dehydriding reaction kinetic mechanism of MgH2-Nb2O5 hydrogen storage materials at 573 K. A new conception, ＂characteristic absorption/desorption time （to）＂ was introduced to characterize the reaction rate The fitting results show that for the hydrogen desorbing mechanism, the surface penetration is the rate-controlling step. The mechanism remains the same even when the original particle size of Nb2O5 is before ball milling （BM） or when the BM time changes And tc indicates that the desorption rate of MgH2-Nb205 will be faster than that of MgHz-Nb205 by BM. The dehydriding reaction rate of MgH2-Nb2O5 （micro particle） BMed for 50 h is 4.76 times faster than that of the MgH2-Nb2O5 （micro particle） BMed for 0.25 h, while the dehydriding reaction rate of MgH2-Nb2O5 （nano particle） BMed for 50 h is only 1.18 times as that of the MgHz-Nb2O5 （nano particle） BMed for 0.25 h. The dehydriding reaction rate of the BMed MgH2-Nb2O5 （nano particle） is 1-9 times faster than that of the BMed MgH2-Nb2O5 （micro particle）.

关 键 词：MgH2-Nb2O5 粉末装管工艺 金属材料 预处理 

分 类 号：TG139.7[一般工业技术—材料科学与工程]