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US 4,284,521 AGranted
Reduced alkaline earth metal powders and process for producing same
AssigneeFerro Corporation
InventorsDavid A. Payne, Sang M. Park, Otto C. Jahnke
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AssigneeFerro Corporation
InventorsDavid A. Payne, Sang M. Park, Otto C. Jahnke
Estimating the term…
An improved polycrystalline semiconducting ceramic composition can be produced from a novel powder which comprises a reduced alkaline earth metal titanate doped with a hexavalent metal oxide such as (MO.sub.3) (Bi.sub.2 O.sub.3).sub.x where M is tungsten or molybdenum, and x ranges from 0 to 7. This powder, which has a mean particle size on the order of less than 10 microns, may be liquid phase sintered with lead germanate to produce a ceramic composition having an extremely fine grain size. By reducing the earth metal titanate (either chemically or gaseously) prior to the liquid phase sintering with lead germanate, particle or grain size growth is substantially eliminated, and the grain size of the ceramic composition is similar to the original particle size of the earth metal titanate.
A reduced alkaline earth metal titanate powder having a mean particle size of less than 10 microns, and a perovskite lattice structure doped with a metal oxide having the formula
A reduced alkaline earth metal titanate powder having a mean particle size of less than 10 microns for use in the manufacture of ceramic capacitors, said powder being produced by calcining alkaline earth metal titanate particles, which have a mean particle size of less than 10 microns or a mixture of alkaline earth oxide or carbonate particles and TiO.sub.2, at a temperature of about 1000.degree.-1400.degree. C. for a period of about 1 to 4 hours, and in an amount of from about 90 to 99% by weight, with a metal oxide doping agent in an amount of from about 1.0 to 10% by weight,
A process for producing a reduced earth metal titanate powder having a mean particle size of less than 10 microns, and the particles of which exhibit n-type semiconductivity, comprising
Dependencies are inferred from the claim text.