Piezoelectric/electrostrictive material and process for production thereof

A piezoelectric/electrostrictive material comprising a BaTiO3-based porcelain composed mainly of BaTiO3 and containing CuO and Nb2O5, characterized in that it has a Curie temperature of 110 to 130° C.

A piezoelectric/electrostrictive material comprising a BaTiO3-based porcelain composed mainly of BaTiO3 and containing CuO and Nb2O5, characterized in that crystal phase of the porcelain at ambient temperature consists essentially of tetragonal phase and cubic phase.

A process for producing a piezoelectric/electrostrictive material made of a BaTiO3-based porcelain composed mainly of BatiO3 and containing CuO and Nb2O5, comprising the steps of weighing individual raw materials, to give a predetermined composition, mixing and grinding said raw materials, calcinating the resulting mixed powder in air at 850 to 950° C., grinding the resulting calcinated material until the ground material comes to have a specific surface area of 7 m2/g or less, molding and firing the ground material to form said porcelain, and, subjecting said porcelain to a heat treatment wherein a temperature is increased up to a maximum temperature of 150° C. to 600° C., and this temperature is kept for 1 to 180 minutes, and thereafter the temperature is decreased to 50° C. or less at a decreasing speed of 50 to 200° C./hr.