Slip casting of barium zirconate aqueous concentrated suspensions

Abstract

The rheological behaviour of aqueous suspensions of barium zirconate was studied focusing on the effect of the volume fraction of particles, leading to the determination of the maximum packing fraction. Optimised suspensions dispersed with both polymethacrylic acid and tetramethylammonium hydroxide were slip cast on plaster moulds to produce discs and crucibles, leading to relative green densities greater than 62% of theoretical ones. Densification was studied at temperatures ranging from 1450 to 1700• C by static and dynamic sintering experiments. Scanning electron microscopy studies demonstrate that slip cast parts are dense and very homogeneous, without any significant processing-related defects or abnormal grain growth.

Dispersion of TiO2 nanopowders to obtain homogeneous nanostructured granules by spray-drying

“…It is therefore clear that research on the dispersion and stabilisation of nanosuspensions in general and nanotitania suspensions in particular is still incipient. Further research is then necessary for obtaining stable high solids content nanosuspensions 10,11 to be used in subsequent processing steps such as spray-drying of powders to produce granules with improved flowability and uniformity for different applications, such as the coating by plasma spraying.…”

Slip casting of nanozirconia/MWCNT composites using a heterocoagulation process

“…[5][6][7][8] The colloidal processing approach allows to obtain welldispersed CNTs-ceramic concentrated suspensions and the production of complex-shaped parts with a decreased number of flaws and smaller pores and higher reliability. 9 However, most wet forming routes, such as slip casting, in situ coagulation moulding, gel casting or tape casting, require stable slurries with high solids loading and low viscosity, [10][11][12][13][14][15] which are difficult to achieve with nanosized particles [16][17][18] and becomes more and more difficult as the shape factor increases, as in the case of CNTs.…”

Gel casting of aqueous suspensions of BaTiO3 nanopowders

“…Slip casting is a well known technique for consolidating ceramic suspensions into complex shapes [11], although long times can be required, especially for nanosuspensions where the water filtration occurs with more difficulty. A further consequence is that the ultrafine porosity in the structure leads to severe difficulty in drying the parts without cracking.…”