Design and Construction of Smart Materials Based on Piezoresistive Sensors andMultilayer Actuators

摘要

PTCR (positive temperature coefficient of resistance) barium titanate was theactive material for a ceramic sensor which employed piezoresistivity to detect changes in applied stress. High purity, chemically prepared barium titanate was donor-doped at an optimum level of 0.30 at% lanthanum to provide semiconductivity. A transition metal counterdopant was added at a level of less than 0.10 at% in some cases, to enhance the PTCR effect. The donor dopant and counterdopant were added to the powder through a special precipitation technique. Tape-cast sheets of undoped and PTCR BaTiO3 were laminated to produce a three-