DESIGN, ASSEMBLY AND CHARACTERIZATION OF COMPOSITE ...

for all these inks. A non-contact planetary mixer (AR-250, THINKY, Tokyo, Japan) is
used after each material addition in all the procedures involved. Due to the lengthiness of
processing steps and various compositions involved, brief descriptions are provided in the
following paragraphs, and detailed ink formulation is listed in Table 6.1.
Preparation of aqueous LFBT ink involves four steps. First, aqueous suspensions
of BT, ZnO, and zinc borate powders are prepared separately with solid volume fraction
calculated for each. Second, calculated amounts of BT, ZnO, and zinc borate suspensions
are added together and mixed thoroughly. Third, appropriate amount of as-received
crystalline lithium acetate dihydrate is added to the mixture and is expected to completely
dissolve in the aqueous medium during process. Finally, an appropriate amount of 25%
by weight PEI-50K stock solution, HPMC stock solution, and DI water are added to
control rheological behavior. The PEI-50K is the flocculating agent for the suspension to
counteract the dispersing behavior of Darvan 821A and the HPMC stock solution and DI
water are controlled to achieve a HPMC concentration of 7 mg/mL in the aqueous
medium and reach solid volume fraction φsolids=0.43.
Preparation of Ni'(m) inks involves four steps. First, aqueous suspensions of BT
and Ni are prepared separately with solid volume fraction calculated for each. Second,
calculated amounts of BT and Ni are added together to achieve the desired BT:Ni ratio.
Third, an appropriate amount of as-received lithium acetate dihydrate is added to the
mixture and is expected to completely dissolve in the aqueous medium during processing.
Finally, an appropriate amount of 25% by weight PEI-50K stock solution, HPMC stock
solution, and DI water are added to control rheology. The PEI-50K is to flocculate the
suspension while the HPMC stock solution and DI water are to achieve a HPMC
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