Accession Number : ADD014712

Title :   Low Temperature Synthesis of High Purity Monoclinic Celsian Using Topaz.

Descriptive Note : Patent Application, Filed 7 Sep 90,

Corporate Author : DEPARTMENT OF THE NAVY WASHINGTON DC

Personal Author(s) : Talmy, Inna G ; Haught, Deborah A

Report Date : 07 Sep 1990

Pagination or Media Count : 10

Abstract : 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)

Descriptors :   *CERAMIC MATERIALS, *ALUMINUM COMPOUNDS, *SILICATES, PATENT APPLICATIONS, ATMOSPHERES, GASES, HEATING, HIGH FREQUENCY, HIGH RATE, HIGH TEMPERATURE, LOW LOSS, LOW TEMPERATURE, MELTING POINT, MIXTURES, POWDERS, PURITY, RESPONSE, SHOCK RESISTANCE, SYNTHESIS, TANGENTS, THERMAL EXPANSION, THERMAL RESISTANCE

Subject Categories : Industrial Chemistry and Chemical Processing
      Ceramics, Refractories and Glass

Distribution Statement : APPROVED FOR PUBLIC RELEASE