Thesis - Oztek_Muzaffer_T_200508_MA

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.
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