Low temperature reactive composite joining

Abstract

Reactive foils and their uses are provided as localized heat sources useful, for example, in ignition, joining and propulsion. An improved reactive foil is preferably a freestanding multilayered foil structure made up of alternating layers selected from materials that will react with one another in an exothermic and self-propagating reaction. Upon reacting, this foil supplies highly localized heat energy that may be applied, for example, to joining lawyers, or directly to bulk materials that are to be joined. This foil heat-source allows rapid bonding to occur at room temperature in virtually any environment (e.g. air, vacuum, water, etc.). If a joining material is used, the foil reaction will supply enough heat to melt the joining materials, which upon cooling will form a strong bond, joining two or more bulk materials.

1 . A product made by a method of bonding a first body to a second body comprising the steps of:
 disposing a freestanding reactive multilayer foil, a wetting layer, and at least one layer of fusible material between the first body and the second body;   pressing the bodies together against the freestanding reactive multilayer foil and fusible material; and   igniting the freestanding reactive multilayer foil,   wherein the product comprises a reacted multilayer foil having a heat of formation more negative than −30 kJ/mol-atom, and wherein the vetting layer is between the reacted multilayer foil and the at least one layer of fusible material, and facilitates surface vetting for the reactive multilayer foil   
   
   
       2 . The product of  claim 1 , wherein the wetting layer comprises copper. 
   
   
       3 . The product of  claim 1 , wherein the wetting layer comprises silver. 
   
   
       4 . The product of  claim 1 , wherein the first and second bodies have coefficients of thermal expansion differing by at least 1 mm/m/° C. 
   
   
       5 . The product of  claim 1 , wherein at least one of the first body and the second body is a semiconductor or microelectronic device. 
   
   
       6 . The product of  claim 1 , wherein the first body comprises metal and the second body comprises ceramic material. 
   
   
       7 . The product of  claim 1 , wherein the wetting layer comprises a material selected from a group of alloys comprising metallic glass, Ag—Sn, Ag—Cu—Ti, Cu—Ti, Au—Sn, and Ni—B. 
   
   
       8 . A bonded structure comprising:
 a first body; and   a second body bonded to the first bock by a joining region comprising a reacted multilayer roil, a wetting layer, and at least one layer of fusible material, wherein the wetting layer is disposed between the reacted multilayer foil and the at least one layer of fusible material, and facilitates surface wetting for the reacted multilayer foil,   and wherein the reacted multilayer foil has a heat of formation more negative than −30 kJ/mol-atom.   
   
   
       9 . The bonded structure of  claim 8 , wherein the wetting layer comprises copper. 
   
   
       10 . The bonded structure of  claim 8 , wherein the vetting layer comprises silver. 
   
   
       11 . The bonded structure of  claim 8 , wherein the first and second bodies have coefficients of thermal expansion differing by at least 1 mm/m/° C. 
   
   
       12 . The bonded structure of  claim 8 , wherein at least one of the first body and the second body is a semiconductor or microelectronic device. 
   
   
       13 . The bonded structure of  claim 8 , wherein the first body comprises metal and the second body comprises ceramic material. 
   
   
       14 . The bonded structure of  claim 8 , wherein the wetting layer comprises a material selected from a list of alloys comprising metallic glass, Ag—Sn, Ag—Cu—Ti, Cu—Ti, Au—Sn, and Ni—B.