Spray Freeze Granulation of Nano Powders for Die Pressing
The processing of nanocrystalline yttria doped zirconia powder via dry forming routes has been investigated via the granulation of the powder using spray freeze drying (SFD). Free-flowing and crushable powders suitable for either die or isosatic pressing have been achieved via the combination of SFD with additions of up to 2 vol% of Freon 11; the latter reducing the strength of the granules whilst not affecting the powder flowability into the die. The approach has allowed relic-free green bodies of up to 55% of theoretical density to be produced using pressures as low as 250 MPa.
Pietro VINCENZINI, Ralf RIEDEL, Alexander G. MERZHANOV and Chang-Chun GE
J. Binner et al., "Spray Freeze Granulation of Nano Powders for Die Pressing", Advances in Science and Technology, Vol. 63, pp. 1-6, 2010