Influence of particles packing in granules on the particles orientation in compacts

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

“…4 In the spray-dryers, a suspension is fed into the drying chamber, then the slip is atomized by pumping it at high pressure through a multi-nozzle array, after that the upward spiralling droplets encounter hot air and fed through a diffuser into the chamber (countercurrent to the droplets). 5 This makes it necessary to prepare and optimise the nanopowder suspensions in order to obtain homogeneous spray-dried granules 6 with high apparent density. Most studies concerning the dispersion and stability of TiO 2 suspensions have been carried out using submicrometer and micrometer sized particles.…”

Non-uniform sintering of yttria-stabilized zirconia powder compact

“…Previous studies on sintering forging on alumina,z irconiaa nd LTCC [ 16 -18] have shown that uniaxial compressive load on sintered samples induces pore orientation. As reported in the introduction, several studies [5,7,9,10] confirmed that uniaxial compaction causes particle rearrangementss uch that elongated particle axes are orientedp erpendicular to the compaction direction. As such, more contacta rea is expected in the axial direction as compared with that in the radial direction.…”

“…(10) and (11). This mismatch( in sinterings trains) is verys mall for all materials except for05LN-8YSZ which is as highas7.5 %.…”

“…Wonish [9] claimed that large average contactarea in the axial direction induced by sinterforging growsmuch more easily than those in the radial direction, which explains the lower axial shrinkage during subsequent free sintering as compared to its radial counterpart. Zainuddin [10] claimed that it is the non-symmetric shape of commercial powder that causes particle orientation. That is, during compaction particles rearrange themselves such that the longitudinal axis falls roughly normal to the compaction axis.…”

Feedstock suspensions and solutions

“…In the spray dryer, a suspension is fed into the drying chamber; then, the slip is atomized by pumping it at high pressure through a multinozzle array; after that, the upward spiralling droplets encounter hot air and are fed through a diffuser into the chamber in a countercurrent flow with respect to that of the droplets (Negre and Sánchez, 1996). In order to avoid undesired agglomerates and obtain homogeneous spray-dried granules with high apparent density, it is necessary to prepare and optimize the suspensions Zainuddin et al, 2011). In order to avoid undesired agglomerates and obtain homogeneous spray-dried granules with high apparent density, it is necessary to prepare and optimize the suspensions Zainuddin et al, 2011).…”