Comparative Study of Solid-Phase and Liquid-Phase Assisted Sintering of Nb₂O₅-Doped Alumina

Abstract:

This work investigated the sintering behavior of alumina doped with 4wt% niobia. Three sintering temperatures were investigated: 1400°C, 1450°C and 1500°C. The first temperature leads to solid-phase assisted sintering (SSS) while the other ones develop liquid-phase assisted sintering (LPS). The presence of liquid phase in the second case is due to an eutectic reaction occurring at 1440°C ± 20°C in the alumina-niobia system. The sintering behavior was assessed by measuring the final densities. The results indicated that the 1400°C solid-state sintering, comparatively, was better. This paper proposes that defects associated to the substitution of Al⁺³ by Nb⁺⁵ in the alumina cation sub-lattice, fostered diffusion and SSS. Sintering at 1500°C presented the lowest density, apparently due to niobate (liquid phase) loss, at this temperature as observed by XRD results.

• Periodical: Materials Science Forum (Volumes 798-799)
• Pages: 691-695
• DOI: https://doi.org/10.4028/www.scientific.net/MSF.798-799.691
• Online since: June 2014
• Authors: Willian Trindade, Marcelo Henrique Prado da Silva, Alaelson Vieira Gomes, Carlos Frederico de Matos Chagas, Luis Henrique Leme Louro, José Brant de Campos
• Keywords: Alumina, Liquid-Phase, Sintering, Solid-Phase

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