Microstructures and electrical properties of Ba_1–xBi_xFe_0·9Sn_0·1O₃thermistor ceramics

Abstract

The polycrystalline Ba 1-x Bi x Fe 0?9 Sn 0?1 O 3 (x50?1, 0?2, 0?3, 0?4 and 0?5) ceramics were prepared using a solid state reaction process, and the effect of Bi substitution on the microstructures and the electrical properties is investigated. The as sintered Ba 1-x Bi x Fe 0?9 Sn 0?1 O 3 ceramics showed the cubic perovskite structure with small amount of spinel BaFe 2 O 4 and some residual Fe 2 O 3 . As the Bi concentration increased, the ceramic grain size decreased and the pores or holes were reduced for the ceramics. The values of room temperature resistivity, thermistor constant and activation energy of the Ba 1-x Bi x Fe 0?9 Sn 0?1 O 3 thermistor ceramics, increasing with the rise of Bi content, were in the range of 1-1290 kV cm, 4469-7328 K and 0?385-0?632 eV respectively. The electrical properties of Ba 1-x Bi x Fe 0?9 Sn 0?1 O 3 thermistor ceramics are mainly attributed to the contribution of grains, grain shells and grain boundaries by the impedance analysis.

Electrical conductivity and temperature sensitivity of Cu/Mo co-modified YFeoO ceramics

“…For improving the properties of the thermistor based on spinel compound, element doping, microstructural modification and process optimization were adopted [10,11]. Meanwhile, the perovskite compounds with the general formula ABO 3 are another choice for the fabrication of NTC materials [12][13][14][15]. The ionic radii of oxygen site and A-site cations are always larger than those at B-site which is located at the oxygen octahedral interstice, hindering the element rearrangement between A-and Bsites.…”