The dielectric properties for (Nb,In,B) co-doped rutile TiO2 ceramics

Recently, colossal permittivities (~105) and low loss factors (<0.1) were reported in (Nb+In) co-doped rutile TiO2 ceramics, which have attracted considerable attention. In this work, (Nb,In,B) co-doped rutile TiO2 ceramics were investigated for achieving temperature- and frequency- stable dielectric properties in TiO2 based colossal dielectric ceramics. The (Nb,In,B) co-doped rutile TiO2 ceramics were prepared by conventional solid-state reaction method. The microstructures, dielectric properties and complex impedance of 1 mol.% (Nb+In) co-doped rutile TiO2 (TINO) and xwt% B2O3 (x=0.5, 1, 2 and 4) doped TINO were systematically investigated and compared. It was found that by doping B2O3 the sintering temperature of TINO ceramics can be reduced by 100 °C. Meanwhile, the dielectric loss of TINO ceramics was decreased by doping B2O3. In the 2wt% B2O3 doped TINO ceramics, the dielectric permittivity kept a high value of >2.0×105 and the dielectric loss was lower than 0.1 in a frequency range of 102−105 Hz and a temperature range of 25-200 °C.