a base metal layer 48 overlies is in contact with and is bonded to the adhesion layer 46 the base metal layer 48 serves three primary functions first it is the material to which the solder bonds in a subsequent soldering operation it must therefore have sufficient strength and must be wetted by the solder second it is an electrical conductor from the solder to the thick film metallization 42 in the final soldered article the base metal layer is thin but it must still have sufficiently low electrical resistivity so as not to add an unduly high electrical resistance third it serves as a diffusion barrier to prevent diffusion of the metal of the underlying thick film metallization 42 into the liquid solder during soldering and into the solder joint during subsequent assembly processes and in service operation this latter consideration has not been recognized in some prior processes wherein the soldering is made directly to a thick film of a precious metal such as gold in these cases the liquid solder and the solid solder during subsequent service dissolves some of the precious metal which in turn forms a low melting alloy at the solder to metallization interface that chemically and mechanically degrades the joint integrity the lowering of the melting point and the microstructural degradation of the solder weakens the creep fatigue resistance of the joint the solder joint is subjected to thermal cycling strains during service and good creep fatigue resistance is required in order to prevent premature failure of the solder joint in these circumstances to perform these.