Bonding metals without brazing alloys

Claim 2

The process as claimed in claim 2, wherein said surfaces are on a pair of workpieces, and said workpieces are selected from the group consisting of metals and metallized and plated ceramics.

Claim 3

The process as claimed in claim 3, wherein one of said workpieces is a metallic body having no more than about 0.0001 inch of a second metal plated at least on said surface.

Claim 4

The process as claimed in claim 4, wherein the other of said workpieces is a body of said second metal.

Claim 5

The process as claimed in claim 5, wherein said first workpiece and said second workpiece are made of eutectic-forming metals, and said heating is carried out at a temperature above their eutectic temperature but below the melting point of either metal

Claim 6

The process as claimed in claim 4, wherein the other of said workpieces has a plated metallic surface comprising one or more layers no more than about 0.0001 inch thick, the surface of one workpiece being capable of alloying with the surface of the other workpiece during bonding.

Claim 7

A process for bonding nominally clean metals, said metals comprising a first workpiece and a second workpiece, said process comprising the steps of: degreasing said workpieces to clean same; heating at least one of said cleaned workpieces to less than about 1,000* F. in a free-oxygen containing atmosphere for a period and at a temperature sufficient to form an oxide coating on said workpiece or workpieces. juxtaposing said first and second workpieces over the desired bond area; heating said first and second workpieces in an atmosphere capable of reducing said oxide and at a temperature sufficient to form a minor proportion of a liquid phase in said bond area; said second heating having a duration sufficient to form a bond between said workpieces; and cooling the bonded workpieces in an atmosphere that prevents reoxidation thereof.

Claim 8

The process as claimed in claim 8, wherein said workpieces are of dissimilar metals forming a eutectic, and said second heating is carried out at a temperature below the melting point of either of said workpieces but above the eutectic temperature of the binary system formed thereby, whereby said liquid phase is formed only in said desired bond area.

Claim 9

The process as claimed in claim 9, wherein one of said workpieces is provided, at least on the desired bond surface, with a thin coating of the metal of said other workpiece, prior to said oxidation step.

Claim 10

The process as claimed in claim 9, wherein one of said workpieces is copper or a high-copper alloy, and said first heating step is carried out in air with an intensity equal to 2 hours at a temperature of about 700* F.

Claim 11

The process as claimed in claim 11, wherein the other of said workpieces is silver or a silver alloy, and additionally comprising coating said copper workpiece with a thin coating of silver prior to said oxidation step.

Claim 12

A process for bonding first and second workpieces, said first workpiece being selected from the group consisting of copper, nickel, iron and alloys of copper, nickel and iron, said second workpiece being selected from the group conSisting of silver and a silver alloy, said process comprising the steps of: degreasing said workpieces to clean same: heating said first, cleaned workpiece to less than about 1,000* F. in a free-oxygen containing atmosphere for a period and at temperature sufficient to form an oxide coating on said first workpiece; juxtaposing said first and second workpieces over the desired bond area; heating said workpieces in an atmosphere capable of reducing said oxide and at a temperature in the range of about 1,400* to 1,600* F.; said second heating having a duration sufficient to bond the workpieces over at least 90 percent of the interfacial bond area; and cooling the bonded workpieces in a protective atmosphere which prevents reoxidation of the workpieces.

Claim 13

The process as claimed in claim 13, and additionally comprising plating said first workpiece with about 0.0001 inch of silver prior to said oxidation step.

Claim 14

The process as claimed in claim 13, wherein said oxidation is carried out by heating in air with an intensity equal to 700* F. for about 2 hours.

Claim 15

The process as claimed in claim 13, wherein said first workpiece is iron or steel, and additionally comprising nickelplating at least the desired bond area prior to said oxidation step.

Claim 16

The process as claimed in claim 16, and additionally comprising silver- or copper-plating said nickel-plated workpiece prior to said oxidation step.

Claim 17

A process for bonding a refractory metal workpiece to a second metal workpiece comprising: degreasing said workpieces to clean same; providing on said cleaned workpieces in at least the bond area at least two plated layers of metals capable of alloying under bonding conditions; heating at least one of said workpieces in a free-oxygen containing atmosphere for a period and at a temperature sufficient to form an oxide coating thereon but less than about 1,000* F.; juxtaposing said workpieces over the desired bond area; heating said workpieces in an atmosphere capable of reducing said oxide and at an intensity sufficient to alloy said layers; and cooling the bonded workpieces in a protective atmosphere.