Effect of sintering procedure on the resistivity of (1-x)BaTiO3-x(Bi0.5Na0.5) TiO3 ceramics

The experimental results on the effect of sintering procedure on the resistivity of high Curie point (1-x)BaTiO3-x(Bi0.5Na0.5)TiO3 (x = 0.5, 2, 4, 6, 8, 10, 15,20 mol%) ceramics, are reported. The sample with x = 0.5 mol% could be semiconducting in air atmosphere sintering, with the Curie point about 149.7 degrees C. The samples with x >= 2 mol% must be sintered at reducing atmosphere. The highest Curie point (about 192 degrees C) with superior PTC effect could be obtained at the sample with x = 4 mol% when sintered at 1290 degrees C for 20 min and added 5 g graphite in the crucible for reducing atmosphere. Samples with more BNT contents could not be semiconducting by this sintering procedure. The samples with weak NTC effect could be obtained by firstly air or reducing atmosphere sintering and then different reducing atmosphere treatment. At last, all of the samples with different BNT contents could be semiconducting according to changing sintering atmosphere and procedure. (c) 2010 Elsevier B.V. All rights reserved.