Thesis - Oztek_Muzaffer_T_200508_MA

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2.3. Sample Preparation LaNi 5 and Mg 2 Ni samples were prepared by ball milling the alloys. LaNi 5 Al x samples were prepared by milling Al with LaNi 5 . VTiNi samples were prepared by milling the stoichiometric amounts of V, Ti and Ni. Ball milling was done in either of the mills for LaNi 5 . For the other materials, the Spex8000 Mixer Mill was used. The milling time was 10, 30 or 90 minutes and the ball to powder ratio was 10 to 1 or 1 to 1. For milling periods greater than 30 minutes, the milling was done in 30 minute periods, followed by 15 minute cool-down periods. Milling was done with 100-300 rpm and 1725 rpm in Fritsch and Spex 8000M mills, respectively. After milling, the vials were opened in the glove box and the samples were first transferred to glass vials for storage, and then portions were loaded in a DSC sample boat. Some samples were AuPd or Pt coated prior to testing. They were first prepared by ball milling. Coating was done by an Emitech K550 type sputter coater at 20 mA. The thickness of coating was controlled by setting the duration of coating. The dependence of coating thickness on duration of coating had been determined by previous users of the coater, and is given in Figure 8. 32
450 400 coating thickness (Å) 350 300 250 200 150 100 0 1 2 3 4 5 duration of coating (min) Figure 8. Coating thickness dependence on coating duration. 2.4. Sample characterization and Analysis A Rigaku Multiflex X-ray diffractometer using Cu Kα radiation, was employed to characterize LaNi 5 +Al samples. Analysis was done over a 2θ range of 20º to 80º. The slit width and scanning speed were 0.020 mm and 2.400 degrees per minute, respectively. The X-ray generator voltage and current were set to 40 kV and 30 mA, respectively. Samples were supported on a metal sample holder whose bottom was closed by scotch tape and the sample was filled above it. Data were analyzed by Jade analysis software. Elemental analysis of LaNi 5 and Al doped LaNi 5 was done by flame emission spectroscopy using a Varian Inc. SpectrAA10 spectrometer. Lanthanum, nickel, and 33
Page 1 and 2: RECOVERY OF HYDROGEN AND HELIUM FRO
Page 3 and 4: ABSTRACT Waste streams of hydrogen
Page 5 and 6: I dedicate this work to my family m
Page 7 and 8: I also would like to cheer for my f
Page 9 and 10: 2.2.2.1. Hydriding and Dehydriding
Page 11 and 12: LIST OF FIGURES Figure 1. Pressure-
Page 13 and 14: Figure 34. Pressure profiles under
Page 15 and 16: 1. INTRODUCTION The focus of this s
Page 17 and 18: ecause of the difference in partial
Page 19 and 20: hydrides by dissolving large amount
Page 21 and 22: hydrogen storage alloy has a specif
Page 23 and 24: • Insensitivity to poisoning by i
Page 25 and 26: hydrogen capacity was not reproduci
Page 27 and 28: showed the lowest plateau pressure
Page 29 and 30: grain boundaries increases the tota
Page 31 and 32: These parameters are generally inte
Page 33 and 34: Figure 4. CaCu5-type P6/mmm structu
Page 35 and 36: In this study, the addition of Al t
Page 37 and 38: 2. EXPERIMENTAL 2.1.Chemicals and R
Page 39 and 40: Figure 5. The high energy Spex 8000
Page 41 and 42: 2.2.1.1. Hydriding and Dehydriding
Page 43 and 44: approximately 5 atm, and heating th
Page 45: determined by the start and end of
Page 49 and 50: 3. RESULTS AND DISCUSSIONS 3.1. Hyd
Page 51 and 52: DSC 111 heat flow/mW Exo 300 Figure
Page 53 and 54: The thermogram associated with the
Page 55 and 56: total time was broken into three 30
Page 57 and 58: The VTiNi sample was subjected to d
Page 59 and 60: solid solution of hydrogen rather t
Page 61 and 62: DSC 111 Heat Flow/mW 180 Exo Figure
Page 63 and 64: 100 rpm setting, the milling vial w
Page 65 and 66: BPR, 400 rpm, 5 minutes) did not re
Page 67 and 68: Table 1: Effects of various milling
Page 69 and 70: Due to the fast kinetics observed a
Page 71 and 72: The mole % Al after milling was les
Page 73 and 74: Figure 24: Percent hydrogen capacit
Page 75 and 76: the start of the heating period, wh
Page 77 and 78: However, it was noted that the part
Page 79 and 80: percent hydrogen was decreased. The
Page 81 and 82: 3.2.2.4. AuPd and Pt Coating on LaN
Page 83 and 84: 1.0 0.8 (a) (b) Wt. % H absorbed 0.
Page 85 and 86: After dehydriding by the sample, th
Page 87 and 88: 19 18 P (atm) 17 16 15 14 0.74 %Al
Page 89 and 90: GC output, arbitrary units 0 5 10 1
Page 91 and 92: sample was LaNi 5 . This may indica
Page 93 and 94: 30 min. 15 min. Intensity (arb. uni
Page 95 and 96: After milling the percentages of Al
Page 97 and 98:
4. CONCLUSIONS This study has been
Page 99 and 100:
16. Van-Vucht, J.H.N., Kuijpers, F.
Page 101 and 102:
47. Suryanarayana, C., Progress in
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Thesis - Oztek_Muzaffer_T_200508_MA

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