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

2014; Trans Tech Publications; Volume: 798-799; Linguagem: Inglês

10.4028/www.scientific.net/msf.798-799.691

1662-9760

Willian Trindade, Marcelo Henrique Prado da Silva, Alaelson Vieira Gomes, Carlos Frederico de Matos Chagas, Luís Henrique Leme Louro, José Brant de Campos,

Intermetallics and Advanced Alloy Properties

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.