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Disk Preform for Braze Joining Pins to Substrates

IP.com Disclosure Number: IPCOM000049152D
Original Publication Date: 1982-May-01
Included in the Prior Art Database: 2005-Feb-09
Document File: 2 page(s) / 21K

Publishing Venue

IBM

Related People

Miller, WR: AUTHOR [+3]

Abstract

This braze preform has laminated metal layers with a higher melting point central layer that permits a large number of re-heating steps to be added to the substrate without significant degradation of the brazed bond.

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Disk Preform for Braze Joining Pins to Substrates

This braze preform has laminated metal layers with a higher melting point central layer that permits a large number of re-heating steps to be added to the substrate without significant degradation of the brazed bond.

It is known to braze pins to ceramic substrates using a brazing alloy disc (1). However, a pin bond formed with a disc made of a single metal alloy is limited in the number of re-heating cycles that it will withstand without degradation.

In this pin bonding operation, pins 10 are braze bonded to metallurgy pads 12 on substrate 14 with laminated brazed discs 16. The disc 16 has a center layer 18 of a metal with a higher melting point than the outer layers 20 and 22. Preferably, layer 18 is gold or copper, and layers 20 and 22 are formed of an alloy of 80% gold and 20% tin.

The pins 10 can be joined to substrate 14 by either attaching the preform 16 to the head of pin 10 and subsequently brazing the pin to the substrate in a suitable fixture (2). Alternately, the preform discs can be loaded on the heads of the pins in the assembly, the substrate positioned over the pins and preforms, and the assembly heated to form the brazed joint.

The use of a laminated preform for joining pins has a number of advantages, i.e., increased braze strength, no significant fillet collapse after multiple reflows, uniform braze metal volume, no flux contamination, and reduction in the number and size of voids in the fillet....