A METHOD FOR FORMING A BOND BETWEEN SAPPHIRE AND GLASS

摘要

Method for forming a bond (hermetic seal) between sapphire and glass. In the preferred form of the invention, the sapphire and glass surfaces to be bonded each have applied to them thin films of chromium, copper, nickel and gold. The inner chromium film is several hundred angstroms thick, the copper and nickel films have a total thickness of about 10,000 angstroms and together comprise an intermediate film, and the outer gold film is about 20,000 angstroms thick. The thin films are applied in a vacuum by direct evaporation or vapor plating or by sputtering. A bond or hermetic seal is effected between the gold films on the respective sapphire and glass materials. An indium wire is inserted between the gold films and a clamping force is applied to the sapphire and glass materials to cause the indium wire to deform to increase substantially the indium surface area. In a vacuum, heat is applied to the sapphire, glass and indium materials sufficient to cause the indium to liquify. After a time period, for example, 15 to 20 minutes, the heat is removed and the liquified indium is allowed to solidify. The resulting bond is particularly suitable for use in forming a hermetic seal between the sapphire faceplate and glass envelope of a cathode ray tube.