Zr-vo Hydrogen Storage Alloy Composition, Structure And Performance Studies

Based on hydrogen storage capacity of intermetallic compounds research status and the results of ZrV₂ alloy, the Ti2Ni-type η -phase Zr₃V₃O_x intermetallic compounds was chosen to be experimental material which oxygen was induced into Zr-V system. Synthesis, physical chemistry properties and the relation between composing, crystal structure and hydrogen storage properties of Zr₃V₃O_x intermetallic compounds were carried out.The oxygen-containing Ti₂Ni-type η -phase Zr₃V₃O_x intermetallic compounds was prepared for the first time in domestic area. The annealing treatment technics and hydrogen storage capacity of Ti₂Ni-type η -phase Zr₃V₃O_x intermetallic compounds research were carried out. The studies on absorption and desorption P-C-T curves of Zr₃V₃O_x intermetallic compounds, the desorption studies, effect of different condition (initial pressure, temperature ect.) and oxygen content on hydrogen storage capacity of Zr₃V₃O_x intermetallic compounds and effect of oxygen content on Zr and V binding energy were hardly reported overseas.Investigation results indicated η -phase Zr₃V₃O_x intermetallic compounds could be prepared by arc-melting the appropriate quantities of metallic Zr, metallic V and V₂O₅. By varying the amount of oxygen, it could control the amount and composing of the second phase without obvious influence to the main phase. The better heat treatment condition of Zr₃V₃O alloy was annealed at 1150℃ for 96h and 1000℃ for 96h, chemical components of alloy was well-distributed through this condition, the amount of n -phase was 90 %. After saturation absorbing deuterium, alloy was turned into Ti2Ni-type single n. -phase Zr₃V₃OD_x This supported a new method to remove different phases of η -phase intermetallic compounds. The better annealing treatment of Zr₃V₃O alloy was annealed at 1150℃ for 96h and 1000℃ for 96h, then saturation absorbing deuterium, the amount of η -phase was 97% through this condition.η-phase Zr₃V₃O_x intermetallic compounds was easily absorbed deuterium fast at room temperature. Gases in Zr₃V₃O_x intermetallic compounds could be removed at 600℃. At room temperature, the capacity was less than 4.5 D/Zr₃V₃O, absorbing and desorbing equilibrium pressure was below 10^-4 Pa, when 1.5≤D/Zr₃V₃O≤3.5, absorption enthalpies and entropies were almost consistent with desorption's; thus, when D/Zr₃V₃O>3.5, absorption enthalpy was about l0KJ/mol D₂ higher than desorption's, it showed there was a very little heel effect. And absorption entropy was about 5 J/K mol. D₂ higher than desorption's, it showed that heel effect was obvious so that Zr₃V₃O alloy was favorable to store hydrogen. The initial absorbing deuterium of Zr₃V₃O_x intermetallic compounds was different with temperature andthe amount of oxygen and the hydrogen storage capacity of these compound from 5.5 (D/Zr₃V₃O) up to 7.0 (D/Zr₃V₃O). The phases of saturate Zr₃V₃O_x hydrides were almost consistent with each other, all of them were consist of main phase ( η -phase) and second phase (δ -ZrD_x, C15-type ZrV₂D_x and β -VD_x) even though the amount of oxygen was different. The volume of saturate Zr₃V₃O_x hydrides increase percentages were less than 9%, so that the anti-pulverization ability of Zr₃V₃O_x alloy was better than that of ZrV₂. The store hydrogen capabilities of Zr₃V₃O_x alloy were better when the amount oxygen was between 0.4-0.6 with taking into account the volume increase percentages and the saturate capacity. The onset of deuterium desorption was found to depdend significantly on the amount of deuterium, the temperature and the number of desorption peaks were related to the four different tetrahedral interstices in the η -phase which were occupied by deuterium. This results are in accordance with the deuterium site occupation in the η -phase with neutron powder diffraction in li...