Microstructure And Hydrogen Storage Performance Of Ti_1.1-xFe_0.6Ni_0.3Zr_0.1Mn_0.2Sm_x?x=0-0.08? Alloy

Due to the characteristics of high reversible hydrogen storage capacity,abundant resources and low decomposition pressure of hydride,the Ti-Fe hydrogen storage alloy is considered to be one of the hydrogen storage materials with great application prospects.However,it is difficult to activate the Ti-Fe alloy during hydrogen storage,and the shortcomings of large hysteresis also limit its practical application.Studies have found that the hydrogen storage performances of Ti-Fe based hydrogen storage alloys can be improved by element replacement,surface modification,and catalyst addition.This article analyzes the effect of elemental Sm substitution and ball milling on the microstructure and gas-solid hydrogen storage properties of Ti_1.1Fe_0.6Ni_0.3Zr_0.1Mn_0.2 alloy based on previous studies,and explores the hydrogen absorption and desorption mechanism of the alloy and Intrinsic relationship between thermodynamic properties and modification process.In this paper,the experimental alloy Ti_1.1-xFe_0.6Ni_0.3Zr_0.1Mn_0.2Sm_x?x=0-0.08?was prepared by vacuum induction melting,and the effect of element substitution on the hydrogen storage performance of the alloy was explored by partially replacing Ti with Sm.In addition,the Ti_1.04Fe_0.6Ni_0.3Zr_0.1Mn_0.2Sm_0.06 alloy was ball milled.The microstructure of the alloy was analyzed by XRD,SEM and HRTEM,and it was found that the as-cast alloy was composed of Ti?Fe,Ni?phase,TiMn phase,Ti and Sm phase,and only Ti?Fe,Ni?phase appeared in the ball milling alloy.In addition,as the ball milling time increases,the alloy exhibits amorphization characteristics,and the particle size of the alloy particles decreases significantly.The experiment found that the element replacement method significantly improved the incubation time of the first activation of the as-cast alloy,and as the amount of Sm element replacement increased,the alloy's first hydrogen absorption incubation period decreased first and then increased.The increase of Sm substitution can also significantly improve the hydrogen absorption rate of the alloy.At 313 K,the hydrogen absorption saturation rate of the alloy within 200 s increased from 83.4%to 96.5%;at 373 K,the alloy hydrogen absorption saturation rate increased from 94%It increased to 98.5%,but the increase in Sm substitution caused the maximum hydrogen evolution of the alloy to decrease significantly.In addition,it has been found that the mechanism for controlling the absorption and release of hydrogen by the alloy is carried out by the three-dimensional diffusion of hydrogen atoms.For the thermodynamic properties of the alloy,the substitution of Sm has little effect on the thermodynamic?H and?S values of the hydrogen absorption and desorption of the alloy.The experiment also studied the effect of ball milling time on the microstructure and hydrogen storage performance of Ti_1.04Fe_0.6Ni_0.3Zr_0.1Mn_0.2Sm_0.06 alloy.The study found that ball milling did not change the structure of the alloy,but the alloy showed amorphous and nanocrystalline shapes after ball milling.After the ball milling,the average particle size of the alloy particles decreased from 100?m to about 10?m,and serious agglomeration occurred.Compared with the as-cast alloy,the incubation period of the first activation of the ball-milled alloy increased significantly.When the ball milling time was 1 h,the alloy had the fastest hydrogen absorption rate.In addition,the ball milling process slightly increased the thermodynamic?H and?S values of the hydrogen absorption and desorption of the alloy,and the increase in the ball milling time significantly reduced the maximum hydrogen absorption of the alloy...