Low firing phosphate-bonded alumina dielectric having improved adhesion to metal
Abstract
Abstract AN ALUMINA DIELECTRIC OF FINE GRAINED STRUCTURE AND HIGH TENSILE STRENGTH CONTAINING FROM ABOUT 2% TO ABOUT 12% BY WEIGHT OF A GLASSY PHASE WHICH BONDS THE FINELY DIVIDED ALUMINA GRANS TOGETHER, THE GLASSY PHASE CONTAINING AT LEAST U% CALCIUM PHOSPHATE AND ONE OR MORE FLUX ADDITIVES, CONSISTING OF LITHIUM SILICATE, ZINC SILICATE, CALCIUM SILICATE OR MAGNESIUM SILICATE IN AN AMOUNT EQUAL TO THE CALDIUM PHOSPHATE AND FORMED THROUGH REACTIVE SINTERING AT FROM ABOUT 1350*C. UP TO 1460*C. WHICH IS 50-200* LESS THAN THAT OF ALUMINA PER SE (1550*C.). THE DIELECTRIC WHICH ADHERES TO NOBLE METALS IS CHARACTERIZED BY HIGH ELECTRICAL VOLUME RESISTIVITY OF 10**12-10**14 OHM-CM., LOW DISSIPATION FACTOR, LOW THERMAL EXPANSION FROM 65 TO 67.6 IN./IN.*C. AND HIGH DENSITY FROM 3.40 TO 3.86 GM.-CU. CC. THE SHRINKAGE OF THE PREFERRED EMBODIMENTS IS ABOUT 17.0-18.0% IN COMPARISON WITH A SHRINKAGE 18.5% FOR ALUMINA TO WHICH NO FLUX IS ADDED. SURFACE ROUGHNESS VALUES AS LOW AS 2 TO 4 MICROINCHES ARE ACHIEVED.
Inventors
- 👤 Relva C Buchanan
Bibliographic Details
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| 3.5 Years (Year 4) | 1974-01-25 | 1974-07-27 | 1975-01-26 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-01-25 | 1978-07-27 | 1979-01-26 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-01-25 | 1982-07-27 | 1983-01-26 | $7700.00 | Window Closed / Lapsed |