Influence of nanoscale additives on the sintering temperature of aluminum oxide

Abstract

As an initial sample of aluminum oxide, we used material of industrial production for the manufacture of ceramic products. Aluminum oxide powders were prepared as additives introduced into the basic material in an amount of 3% by mass obtained by electric wire explosion as well as in combustion reactions of nitrate-polymer precursor based on polyvinyl alcohol. The obtained additives were characterized in terms of the structure and particle morphology. The samples of the first type included a mixture of different modifications of aluminum oxide, the second type included hydrated aluminum oxide. The first two samples consisted mainly of unaggregated spherical nanoparticles with specific surface area of 20 and 69 m2/g, and the powder obtained in combustion reactions contained flat flake particles, it had a specific surface area of 8 m2/g. The introduction of nano-sized additives led to a shift of the dilatometric sintering curve of compacted samples to lower temperatures, up to 140 degrees maximum. The sample with the largest specific surface was more active in lowering the sintering temperature. The result obtained for the pyrolytically synthesized additive was comparable with the above-mentioned shift in the sintering curve.

Keywords

• aluminum oxide
• sintering
• nanoscale additives
• electric wire explosion method
• nitrate-polymer precursor combustion method