Low Temperature Synthesis of High Purity Monoclinic Celsian Using Topaz.
Patent Application, Filed 7 Sep 90,
DEPARTMENT OF THE NAVY WASHINGTON DC
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This invention relates to ceramics and more particularly to aluminosilicate ceramics. Ceramics based on monoclinic celsian BaO-A12O3-2Si02 can be considered for applications requiring materials with a combination of high melting point, low thermal expansion, high thermal shock resistance, high-frequency working capabilities, low and thermally stable dielectric constant and low loss tangent. A process for preparing monoclinic celsian from topaz and BaCO3, powders by heating an intimate mixture of the powders at a temperature of from 900 degree C to less then 1590 degree C in an atmosphere of the gases generated by the monoclinic celsian formation reaction itself. ttl
- Industrial Chemistry and Chemical Processing
- Ceramics, Refractories and Glass