Piezoelectric ceramic and manufacturing method thereof

摘要

There is provided a piezoelectric ceramic having a small mechanical factor of merit Qm and excellent heat-resisting properties, e.g., a piezoelectric ceramic for filter elements which is compatible with surface mounting and a method of manufacturing the same in a large amount and in a stable manner. There is provided a piezoelectric ceramic which is a composite oxide of at least lead, zirconium and titanium, wherein an oxide of manganese exists in a grain boundary layer in a density higher than that in a crystal grain of the piezoelectric ceramic and a glass phase exists in the grain boundary layer. It is manufactured by depositing a manganese compound and a glass material on the surface of a piezoelectric ceramic comprising a composite oxide of at least lead, zirconium and titanium and by performing thermal processing thereafter to diffuse the deposited substance in a grain boundary portion of the piezoelectric ceramic.