Structure and Property of Y and YF_3 Doped Barium Titanate

Positive Temperature Coefficient of Resistivity (PTCR) materials based on Yttrium and Yttrium Fluoride (YF_3) doped Barium titanate (BaTiO_3) ceramics were prepared in different sintering atmospheres, respectively. The effects of sintering atmospheres on the microstructure, property and mechanism of substitution of doped BaTiO_3 cerajmics were investigated by the means of XRD, SEM, XRF and R-T measuring instrument. Sintering in a low oxygen partial atmosphere can increase the densities of Y and YF_3 doped BaTiO_3 and make grain particle grow. Both Y and YF_3 doped BaTiO_3 ceramics are n-type semiconductor in which Y substitutes A-site and F substitutes O-site. Sintered in a argon atmosphere, Y doped BaTiO_3 exhibited little PTCR effect, however, an anomalous PTCR effect was observed when 0.3mol% YF_3doped BaTiO_3 ceramics was fired in Argon atmosphere. This phenomenon may be explained by a new O site substitution mechanism.