Abstract: A method for joining, by molecular diffusion, an element of greater electrical resistance to a surface of substantially lesser electrical resistance. A piece of resistive material capable of being spot welded to the element of greater electrical resistance is placed in contact with both the surface having substantially lesser electrical resistance and the element having the greater electrical resistance. The resistive piece and the resistive element are spot welded to each other, whereby the heat from that spot weld causes the conductive material to be joined to the piece of resistive material by molecular diffusion. The method is particularly useful for joining nichrome wire to copper-clad printed circuit boards and for joining metal fasteners to copper and aluminum sheet metal surfaces.

Abstract: A method for fixing an abradable material of random interlocked metallic fibers sintered and pressed to a specified thickness and density in place on a substrate is set forth where the abradable material bonded to a metal backing plate is placed with the metal backing plate engaging a substrate. The abradable material is compressed without heat to substantially a solid mass at spaced spots; the compressed spots are heated by electrical resistance to a sintering temperature and pressed to form a solid mass. The solid mass of each spot of abradable material is heated to an increased temperature by electrical resistance, welding the solid mass of abradable material to the substrate by completely penetrating the backing plate and forming a weld nugget.