Semiconductor ceramic composition and process for producing the same

• Main Authors: SHIMADA TAKESHI, TOJI KAZUYA
• Format: Patent
• Language: English
• Published: 09.08.2011
• Subjects: ARTIFICIAL STONE; BASIC ELECTRIC ELEMENTS; CABLES; CEMENTS; CERAMICS; CHEMISTRY; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDINGMATERIALS; CONCRETE; CONDUCTORS; ELECTRICITY; INSULATORS; LIME, MAGNESIA; METALLURGY; REFRACTORIES; RESISTORS; SELECTION OF MATERIALS FOR THEIR CONDUCTIVE, INSULATING ORDIELECTRIC PROPERTIES; SLAG; TREATMENT OF NATURAL STONE

It is intended to provide a semiconductor ceramic composition in which a part of Ba in BaTiO3 is substituted with Bi-Na, which is capable of restraining the evaporation of Bi in the calcination step, is capable of restraining the compositional deviation of Bi-Na thereby suppressing the formation of different phases, is capable of further reducing the resistivity at room temperature, and is capable of restraining the fluctuation of the Curie temperature; and to provide a production process of the same. When a calcined Ba(TiM)O3 powder (M is a semiconductor dopant) and a calcined (BiNa)TiO3 powder are separately prepared and the Ba(TiM)O3 powder is calcined at a relatively high temperature while the (BiNa)TiO3 powder is at a relatively low temperature, both at the most suitable temperatures for them, then the evaporation of Bi may be retarded and the compositional deviation of Bi-Na may be thereby suppressed to inhibit the formation of different phases; and when these calcined powders are mixed, formed and sintered, then a semiconductor ceramic composition which has a low resistivity at room temperature and is capable of restraining the fluctuation of the Curie temperature can be obtained.