Method for fabricating large dimension bonds using reactive multilayer joining

A method of forming a bonded plate assembly, comprising the steps of:

• providing a brass plate having a top surface, and pre-wetting the top surface with a solder layer;
• providing a nickel plate having a bottom surface, and pre-wetting the bottom surface with a solder layer;
• introducing a plurality of discrete pieces of bonding foil in a laterally adjacent and spaced apart arrangement in a common plane parallel to, and between, the top surface of the brass plate and the bottom surface of the nickel plate, wherein each discrete piece of the bonding foil is an ignitable heterogeneous stratified structure for the propagation of an exothermic reaction;
• interconnecting each spaced apart and laterally adjacent discrete piece of bonding foil with at least one bridge structure capable of transferring an exothermic reaction across an interspatial gap separating one laterally adjacent piece from another;
• and,
• pressing the brass plate and the nickel plate together and initiating an exothermic reaction in at least one of said discrete pieces of the bonding foil introduced there between to melt and bond the solder layer on the brass plate with the solder layer on the nickel plate without affecting the microstructure or flatness of the nickel plate in the formation of the bonded plate assembly.