Thermal processing and properties of BaTi4O9 and Ba2Ti9O20 dielectric resonators

摘要

Sn-doped and undoped barium titanates pressedpowder pellets were sintered at 1360 and 1390℃for 5h. Thoughbatched to form Ba2Ti9O20, a two-phase microstructure ofBaTi4O9 and TiO2 formed from the undoped system. Thedielectric constant at 6 Ghz was 40 without SnO2additions.Doping with 1.64 mol% SnO2 stabilized Ba2Ti9O20 andformed a single-phase microstructure but resulted in higherporosity. Dilatometry studies implied that SnO2 additionsfacilitated a greater fraction of reaction to occur in the solid state,causing a lower quantity of pore-filling fluid to form above 1317℃. As a result of the higher porosity, the dielectric constantsand quality factors were also reduced.