An Investigation On The Electrochemical Hydrogen Storage Of The Ti-V Based BCC Alloys Surfaced With AB_x (x=3,3.5,5)

This paper analyses the adding Mn element to Ti-V-Cr department, its influence of storing hydrogen performance, optimized out alloy Tio.25Vo.3Cro.4Mno.o5 with better comprehensive performance on this basis;Then prepareing Ti_0.25V_0.3Cro.4Mn_0.05 -AB_x( x =3.0, 3.5, 5 )through the mechanical alloy method composite , studying its electric chemical property and store hydrogen performance . The main conclusion got is as follows:1. The main phase of the cast alloy Ti_0.25V_0.35-xCr_0.4Mn_x (x =0-0.15) smelted by the electric arc furnace of the vacuum is the main phase of BCC solid solution phase and the second phase of C14 Laves phase. With the increasing of Mn content, the cell volume of Ti_0.25V_0.35-xCr_0.4Mn_x (x =0-0.15) alloy is being decreased. After alloy Tio.25Vo.3Cro.4Mno.05 fulling hydrogened, the structure changes from the body-centered cubic (BCC) by the original structure to the face-centered cubic (FCC). The space group is changed from Im-3m (229) into Fm-3m (225). The microscopic structure of the cast alloy Ti_0.25V_0.35-xCr_0.4Mn_x(x =0-0.15) is indicated that with the increase of Mn content, the second phase is shown , which is around the main phase. That is the properly reason that the amount of hydrogen absorption of Ti_0.25V_0.35-xCr_0.4Mn_x (x =0-0.15) reduces with increasing Mn. Studying Ti_0.25V_0.35-xCr_0.4Mn_x (x =0-0.15) thermodynamics at the performance , it is found that the Ti_0.25V_0.35-xCr_0.4Mn_x (x =0-0.15) alloy is difficult to activate under room temperature , up to temperature rises to 473K, it could activate through six times, the alloy could reach the large capacity. From the p-c-T curve of Ti_0.25V_0.35-xCr_0.4Mn_x (x =0-0.15) alloy we can find that with increasing Mn content, the hydrogen storage capacity of the maximum and effective reduce sharply, the smooth of platform increases, the pressure of platform rises.2. The composite alloy Ti_0.25V_0.35-xCr_0.4Mn_0.05-15wt%La_0.67Mg_0.33Ni_3.0 which got by mechanical ball-milling is BCC phase. La_0.67Mg_.33Ni_3.0 alloy as an function of window and passway on the alloy surface of Ti_0.25V_0.3Cr_0.4Mn_0.05, improves dynamics performance. The composite Ti_0.25V_0.3Cr_0.4Mn_0.05-l 5wt% La_0.67Mg_0.33Ni_3.0 is very apt to activate under the room temperature. The adding of La_0.67Mg_0.33Ni_3.0, as the second phase to collect electric current and electric catalysis of Ti_0.25V_0.3Cr_0.4Mn_0.05 alloy,improve the electrochemical reaction speed of the base alloy.lt has the discharge capacity of 190.5mAh/g, and the capacity of circulation 300 times still keeps 93%. During the searching of the suitful process, The weight ratio of the mixed powders to the balls was 1:30, It can be found in ball milling process research which is the rotating speed and ball milling time: when rotating speed smaller than 200r/min, it can not form the composite , it just mixed;When the rotating speed up to 300r/min , it can just form the composite;When greater than 400r/min in rotating speed , it is spread layer each other to transform into , making electric chemical property of the composite drop. To finding the proper ball milling time in the research: With increase that ball milling time , the diffraction peak of composite wide obviously, this is because during the ball milling in the course, the crystalline grain of the composite is thinning and some is non-crystalline. The size of particle of the composite and size of crystalline grain reduced, the activation of this composite is very favorable. With increasing ball milling time, the electrochemical capacity of the composite is reduced, when the ball milling time for 6 hours, the alloy has the largest electrochemical capacity. While the different modifying material influencing composite performance to study, the main impact on electricity chemical property of research, no matter than add AB3 type , A2B7 type , AB5 type alloy , they all can make the vanadium base solid solution alloy Tio.25Vo.3Cro.4Mno.o5 have electrochemistry to discharge performance , and easy to activate, alloy Lao.67Mgo.33Ni3.o of AB3 type have the largest electrochemical capacity.