Santa Barbara Research Center

Raytheon Company

Tom K Evans

Timothy S Romano

Gary B Hughes

Karl H Neumann

Leonard E Peck

Arthur A Eneim

An electrical feedthrough (34) is prepared by furnishing an aluminum oxide feedthrough plate (70) and at least one feedthrough pin (80) having a length greater than the thickness of the feedthrough plate (70). A pin bore (78) is formed through the feedthrough plate (70) for each feedthrough pin (80). Each pin bore (78) has a pin bore (78) size greater than the feedthrough pin (80) size, preferably by an amount no greater than that required to permit the penetration of a brazing metal (88) between the pin bore (78) and the feedthrough pin (80). Each feedthrough pin (80) is inserted into its respective pin bore (78) and brazed into place utilizing a metallic active braze alloy (88) and no glassy seal. The feedthrough plate (70) may be simultaneously brazed to a package structure (22) using active or nonactive brazing.

Electrical feedthrough and its preparation

A gold-coated molybdenum article (30) is made by furnishing a substrate (32) made of pure molybdenum or an alloy of molybdenum, and preparing a slurry of gold powder, acrylic binder, and acetone liquid carrier. The slurry is applied to a portion of a surface of the substrate. The substrate with applied slurry is heated in vacuum or inert atmosphere to an elevated temperature, preferably about 2040.degree. F., and thereafter cooled to ambient temperature. The result is an article (30) having at least a portion of the substrate (32) covered with an adherent gold coating (34).

Preparation of gold-coated molybdenum articles and articles prepared

A vacuum system (20) includes an enclosure (22) having a vacuum-tight wall (26) and an internally threaded aperture (66) through the wall (26). A tip-off fitting (24) has a base (50) with a bore (52) therethrough, a hollow tube (62) fixed to the base (50) with a vacuum-tight seal, such that an interior (64) of the tube (62) is in communication with the bore (52) in the base (50), and an external thread (58) on the exterior of the base (50). The external thread (58) on the exterior of the base (50) is dimensioned to threadably engage the internal thread (68) on the aperture (66). There is a disengageable vacuum sealant (70) such as a layer of indium metal between the external thread (58) of the base (50) and the internal thread (68) of the aperture (66). The vacuum system (20) is evacuated through the tip-off fitting (24) and sealed by closing off the hollow tube (62). At a later time, the vacuum system can be brought to atmospheric pressure and then reseated by replacing the tip-off fitting with another tip-off fitting and repeating the evacuation and sealing.

Semi-permanent vacuum closure with multiple retubulation capability

A lower vacuum housing (34) of a sensor dewar (26) is fabricated in a single brazing operation from ceramic and metallic components. The components are assembled with ceramic-to-metal interfaces and metal-to-metal interfaces. Brazing is accomplished by active brazing of the ceramic-to-metal interfaces and non-active brazing of the metal-to-metal interfaces. Specific combinations of active braze alloys and non-active braze alloys are provided for various combinations of dewar materials.

Brazed lower vacuum housing for a dewar

A feedthrough (34) is formed of a feedthrough plate (44) having at least one bore (46) therethrough and a feedthrough pin (48) hermetically sealed into the bore (46). The feedthrough pin (48) includes an elongated pin (50) having an axis of elongation (52), a recess (54) in at least one end of the pin (50), the recess (54) extending parallel to the axis of elongation (52), and a gold coating (56) within the recess (54). There are preferably a plurality of bores (46) in the feedthrough plate (48) and a corresponding plurality of the feedthrough pins (48). The gold coatings (56) at the ends of the feedthrough pins (48) are desirably lapped to ensure coplanarity and a smooth surface finish especially suited for wire bonding or tab bonding.

Growing community of inventors

Goleta, CA, United States of America

Tom K Evans