TWO PHASE ELECTRICAL MATERIALS BY POWDER METALLURGY TECH- NIQUES

摘要

1520831 Mixed piezoelectric-piezomagnetic material; barium titanate PHILIPS ELECTRONIC & ASSOCIATED INDUSTRIES Ltd 7 Jan 1976 [10 Jan 1975] 00486/76 Headings C1J and C1A A material consisting of a mixture comprising a piezoelectric phase and a piezomagnetic phase and capable of converting an electric field into a magnetic field and vice versa is manufactured by preparing a starting mixture of materials which form a sintered mixture of the phases on heating, heating the starting mixture at a given temperature so as to form a sintered product, and continuing heating until a chemical equilibrium between the phases has been established at the given temperature. After the chemical equilibrium has been established the sintered product may be heated in a chemically active (e.g. oxidizing or reducing) atmosphere. The examples describe the production of a two phase mixture from CoCO 3 , Fe 2 O 3 , TiO 2 and BaCO 3 (Example I) and from BaTiO 3 and Ni 0À97 Co 0À03 M 0À10 Fe 1À90 O 4 (Example II). The BaTiO 3 of Example II is prepared by grinding BaCO 3 and TiO 2 in alcohol in a ball mill, drying and then heating for 16 hours at 1000‹ C.