Coatings

Abstract

Abstract PROVIDED IS AN OVERGLAZE COMPOSITION PARTICULARLY USEFUL FOR PROTECTING A MICROELECTRONIC CIRCUIT FROM ENVIRONMENTAL SHOCK AND CONTAMINATION. SUCH AN OVERGLAZE COMPRISES BY WEIGHT ABOUT 15-60 PERCENT PBO, 12-40 PERCENT B2O3, 5-45 PERCENT ZNO AND PRODUCES, UPON BEING FIRED FROM A PRINTED PASTE AT A FIRING TEMPERATURE BELOW ABOUT 650*C., A VITREOUS GLASS COATING WHICH IS SUBSTANTIALLY HERMETIC IN ITS SEALING CHARACTERISTICS. THE OVERGLAZE COMPOSITION MAY OPTIONALLY ACCOMMODATE UP TO 12 PERCENT BY WEIGHT OF OTHER VARIOUS OXIDES SUCH AS, FOR EXAMPLE, SIO2, CUO, V2O5, BAO, BI2O3, TIO2, ZRO2 AND/OR MAY OPTIONALLY ACCOMMODATE UP TO 25 PERCENT BY WEIGHT OF DISPERSED PARTICULATE CERAMIC MATERIALS. IN ADDITION, THE COATING SO FORMED, WHEN FIRED UPON A CERAMIC SUBSTRATE HAVING A COEFFICIENT OF THERMAL EXPANSION OF LESS THAN ABOUT 100 X 10**-7 IN./IN./*C., EXHIBITS A TENACIOUS BOND AND A STRUCTURAL STRESS AT THE BOND INTERFACE OF BETWEEN ABOUT 2000 P.S.I. IN COMPRESSION TO ABOUT 1200 P.S.I. IN TENSION. PRINTING PASTES ARE FORMED FROM THESE COMPOSITIONS BY ADMIXING THE GLASS PRODUCED, IN PARTICULATE FORM, WITH A CONVENTIONAL LIQUID ORGANIC VEHICLE IN AMOUNTS SUFFICIENT TO RENDER THE PASTES PRINTABLE.

Inventors

• 👤 R Dietz
• 👤 Fadden A Mc

Bibliographic Details