ISSN 0862-5468 (Print), ISSN 1804-5847 (online) 

Ceramics-Silikáty 49, (3) 188 - 194 (2005)


SEMI-CONDUCTING BARIUM TITANATE CONTAINING B₂O₃
 
Erkalfa Hilkat 1, Cesmeci Rustiye 1, Yuksel Berat 2, Ozkan T. Osman 2
 
1 TÜBITAK, Marmara Research Centre, P.O Box 21, Gebze-Kocaeli, TURKEY
2 Istanbul University, Engineering Faculty, Avcilar, Istanbul, TURKEY

Keywords: Semiconduction, Barium titanate, Boron sintering aid
 

The effects of the grain boundary modifiers H₃BO₃ and SiO₂ before and after the calcination steps on the microstructure and on the positive temperature coefficient of resistivity (PTCR) of Sb₂O₃ donor-doped Ti-excess barium titanate (BT) were investigated. The additions before calcination resulted in coarse porosity between the grains and the additions after calcination gave rounded, uniform grains with a pronounced decrease in porosity. The Sb₂O₃ donor-doped BT became conductive when sintered at 1300°C giving a room temperature resistivity (ρRT) of 400 Ohm cm. The ρRT values of the B₂O₃ and SiO₂ contained samples decreased when modifiers were added after the calcination step. The Sb₂O₃ donor-doped BT showed a PTCR effect of 4.2 orders of magnitude and a range of 4.5-5.0 orders of magnitude were obtained for the B₂O₃ and SiO₂ added samples.


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