Wn. Dossantos et al., EFFECT OF ADDITION OF NIOBIUM OXIDE ON THE THERMAL-CONDUCTIVITY OF ALUMINA, Journal of the European Ceramic Society, 18(7), 1998, pp. 807-811
Alumina is extensively used in the advanced ceramic industry, mainly f
or mechanical and electronic applications. However, the high melting p
oint of Al2O3 necessitates a high sintering temperature of around 1923
K. In this work it was investigated the effect of niobium oxide addit
ives on the thermal conductivity of alumina sintered at 1673 K, and at
1723 K. Niobia concentrations added ranged from I to 6% in weight. Th
ermal diffusivity was measured over the temperature range 373-1273 K u
sing the laser flash method. The samples sintered at 1723 K containing
greater than or equal to 3% Nb2O5 show a continuous microstructure co
ntaining little porosity. Nb2O5 additions in the range 3-6% result in
increases in thermal conductivity, the highest increase being noted fo
r the 5 wt% addition. (C) 1998 Elsevier Science Limited. All rights re
served.