Articles

All articles  |  Recent articles

Spray Freeze Granulation of Submicrometre α-Alumina Using Ultrasonication

S. Ghanizadeh^,1, P. Ramanujam^,1, B. Vaidhyanathan^,1, J. Binner^,1,2

¹ Department of Materials, Loughborough University, Loughborough, LE11 3TU, UK
² School of Metallurgy and Materials, College of Engineering and Physical Sciences, University of Birmingham, Edgbaston, Birmingham, B12 2TT, UK.

received August 25, 2016, received in revised form November 12, 2016, accepted November 22, 2016

Vol. 7, No. 4, Pages 455-462   DOI: 10.4416/JCST2016-00078

Abstract

Granulation is a key factor towards improvement of the flowability of fine ceramic powders to make them suitable for industrial dry pressing. Controlled granulation of fine alumina particles with a primary particle size of ∼ 150 nm was carried out using spray-freeze drying, which led to the production of flowable granules with high crushability. The fracture surface of uniaxially die-pressed green bodies made from granules with density values of ≥ 50 % of theoretical showed a uniform microstructure. Sintering experiments were performed using conventional single- and two-stage radiant heating methods followed by density and grain size measurement and characterisation of the final dense compacts to study the efficiency of two-stage sintering in grain growth elimination. The results have been compared with those of alumina bodies prepared using similar suspension by the slip-casting route.

Keywords

Keywords: Alumina, granulation, spray-freeze drying, two-stage sintering

Copyright

Göller Verlag GmbH