Study On Hydrogen Storage Properties And Preparation Of Mg-Ti-Based Alloys

Mg50-xTi40VxNi10(x=0,10,20,30) and Mg76T12Ni12+MH (MH=CaH2, LiH, NaH, LiAlH4) allloys were synthesized by mechanical alloying(MA), the phase structures and hydrogen storage properties of the alloys were investigated by X-ray diffraction and pressure-composition isotherm measurement.For Mg50-xTi40VxNi10(x=0,10,20,30) alloys, the three alloys of Ti40V1,Ti40V20 and Ti40V30 with BCC and FCC structures melted by magnetic levitation melting, Mg power and Ni power were added to prepare Mg50-xTi40VxNi10(x=0,10,20,30). The results show that the main binary alloy phase is consisted of BCC and FCC phase after milled 150 hours. Mg20Ti40V30Ni10 alloy had the largest hydrogen storage capacity of Mg50-xTi40VxNi10(x=0,10,20,30), it was 1.58wt%.Mg76Ti12Ni12+10wt%MH(MH=CaH2, LiH, NaH, LiAlH4) were synthesized by ball milling in hydrogen atmosphere. The Four simples could absorb hydrogen rapidly without activation. After 20 hour milling, the maximum hydrogen absorption capacity for Mg76Ti12Ni12+10wt%MH (MH=CaH2, LiH, NaH, LiAlH4) alloys were 3.78wt%,3.19wt%,3.32wt% and 3.43wt%. The samples all could reach a saturated hydrogen absorption capacity at 300℃in 150 seconds. The first hydrogen absorption rate was found in Mg76Ti12Ni12+10wt% CaH2, and the second one is Mg76Ti12Ni12+10wt%LiAlH4.Mg76Tii2Ni12+(x=2,5,10) wt%CaH2 were synthesized by ball milling in hydrogen atmosphere. The three samples could absorb hydrogen rapidly without activation. The hydrogen absorption capacity was 4.04wt%,4.25wt% and 3.78wt%. Mg76Ti12Ni12+5wt%CaH2 exhibited the best hydrogen storage performance after 20 hour milling. The samples with 2wt%CaH2 and 5wt%CaH2 additive could absorb more than 4wt% hydrogen at 300℃within 90 seconds.