Influence Of Dielectric Barrier Discharge Plasma And Indium Solution On Hydrogen Storage Properties Of Mg-based Alloy

Mg-based alloys are one of the most attractive materials for hydrogen storage due totheir high capacity, abundance and low cost. However, their hydrogen desorption temperatureis too high and their hydrogenation/dehydrogenation kinetics is too poor to satisfy thepractical application. In this paper, Dielectric Barrier Discharge Plasma （DBDP） assisted ballmilling was firstly adopted to prepare Mg-based hydrogen storage alloys and themicrostructure, phase transformation and hydrogen storage properties of Mg85In5Al5Ti5alloyprepared by DBDP assisted ball milling and conventional mechanical milling were alsostudied. In addition, the hydrogen storage properties of Mg（In）₂Ni alloy were also checked.This thesis attempted to improve DBDP assisted ball milling device, which cansuccessfully achieve dielectric barrier discharge plasma in hydrogen atmosphere. It was foundthat DBDP assisted ball milling in hydrogen atmosphere could obviously refine the size of Mgparticles. Mg powder reacted with hydrogen and formed MgH2after0.5hr and2hrs underDBDP assisted ball milling in hydrogen atmosphere, when the discharge current of1.0A and0.5A was applied, respectively. Mg and Ni （2:1） mixture reacted with hydrogen and formedMgH2after2hrs under DBDP assisted ball milling in hydrogen atmosphere, when thedischarge current of0.5A was applied.The dehydrogenation reaction enthalpy was lowered to about60kJ/mol forMg85In5Al5Ti5alloy under DBDP assisted ball milled for4.0hours from74kJ/mol for that ofpure magnesium. The dehydrogenation temperature was about556.9K, when thedehydrogenation plateau pressure was0.1MPa.The dehydrogenation kinetics ofMg85In5Al5Ti5alloy prepared by DBDP assisted ball milling are better than that prepared bymechanical milling, and the activation energy of Mg85In5Al5Ti5alloy prepared by DBDPassisted ball milling was about124.3kJ/mol, which fell by perhaps10%and20%fromMg85In5Al5Ti5alloy prepared by ball milling and pure magnesium, respectively.Mg （In）2Ni alloy is synthesized by the method of mix-sinter-milling, Indium soluted inthe alloy during the hydrogenation and dehydrogenation process. From the van’t Hoff plot,the dehydrogenation reaction enthalpy is different between high temperature region and low temperature region, excluding the reason of instrument and test method. The dehydrogenationreaction enthalpy and entropy of Mg（In）₂Ni alloy is about63.2kJ/mol and119.3J/K.mol inthe low temperature region, which is a little lower than that of pure Mg2Ni alloy. Theproperties of high temperature region should be further studied. The activation energy of Mg（In）2Ni alloy is23.6kJ/mol. Mg（In）₂Ni alloy could dehydrogenate at467K.