Braze alloy containing particulate material

Abstract

A minimum joint thickness can be assured by incorporating beads or particles having a diameter corresponding to the joint thickness desired and which are infusible at the brazing temperature. Preferably such particles are formed of high-melting metals, metal oxides, ceramics, or cermets and are mixed into the alloy paste prior to fusing. In a preferred embodiment, the particle-containing paste is mixed with a non-flux carrier to facilitate application to the elements to be brazed. Exemplary application methods may include painting, rolling, screening, or extrusion dispensing. Brazing alloys in accordance with the invention are useful in bonding ceramics to ceramics, ceramics to metals, and metals to metals.

1 . A particulated braze alloy for use in brazing over a predetermined range of brazing temperatures, comprising: 
 a) at least one metal fusible within said temperature range; and    b) a particulate material mixed with said fusible metal, said particulate material being infusible within said temperature range.    
   
   
       2 . A particulated braze alloy in accordance with  claim 1  wherein said particulate material is provided in a predetermined particle size range.  
   
   
       3 . A particulated braze alloy in accordance with  claim 2  wherein said size range is between about 30 μm and about 50 μm.  
   
   
       4 . A particulated braze alloy in accordance with  claim 1  wherein said particulate material is selected from the group consisting of metals, metal alloys, ceramics, and cermets.  
   
   
       5 . A particulated braze alloy in accordance with  claim 1  wherein the shape of particles in said particulate material is selected from the group consisting of irregular and spherical.  
   
   
       6 . A particulated braze alloy in accordance with  claim 1  wherein said alloy includes silver.  
   
   
       7 . A particulated braze alloy in accordance with  claim 1  comprising an element selected from the group consisting of copper and vanadium.  
   
   
       8 . A particulated braze alloy in accordance with  claim 1  wherein said temperature range is between about 900° C. and about 1000° C.  
   
   
       9 . A particulated braze alloy in accordance with  claim 1  wherein the melting temperature of said particulate material is at least about 50° C. higher than said temperature range.  
   
   
       10 . A particulated braze alloy in accordance with  claim 1  further comprising an evanescent non-flux carrier.  
   
   
       11 . A particulated slurry for forming a brazed joint, comprising: 
 a) a metal alloy;    b) a particulate material; and    c) an evanescent non-flux carrier.    
   
   
       12 . A brazed joint, comprising: 
 a) a first element having a first surface;    b) a second element having a second surface; and    c) a braze seal disposed between said first and second surfaces, said seal being formed of a particulated braze alloy.    
   
   
       13 . A joint in accordance with  claim 12  wherein said seal has a predetermined thickness corresponding to the diameter of particulates in said particulated braze alloy.  
   
   
       14 . A joint in accordance with  claim 12  wherein said first element is formed of a metal and said second element is formed of a ceramic.  
   
   
       15 .- 16 . (canceled)