Fabrication of Barium Lead Titanate Ceramics by Hot-Pressing and Their PTCR Effects
1985 Volume 93 Issue 1084 Pages 791-795
Details
1985 Volume 93 Issue 1084 Pages 791-795
The PTCR (positive temperature coefficient of resistivity) characteristics in hot-pressed semiconducting barium lead titanate ceramics with the composition of Ba0.35Pb0.65TiO3 have been investigated and compared with those in the porous ceramics with the same composition, which have been confirmed to exhibit the PTCR effect of more than four orders of magnitude. Influences of heat-treatments and the addition of Mn on the PTCR characteristics in the hot-pressed materials were also examined. The results obtained are summarized as follows:
(1) Too much densification of PTCR materials causes a smaller PTCR effect.
(2) Heat-treatment above 1200°C yields a complicated influence on the electrical conduction of the material through both grain growth and change of the composition due to the vaporization of PbO.
(3) The addition of Mn in the hot-pressed materials resulted in no significant improvement of the PTCR characteristic, but a slight improvement was observed at a doping concentration of less than 0.03mol%.
