Abstract: A heat-conductive composite material usable as a substrate (heat sink) for mounting a semiconductor thereon or a lead frame is provided, which comprises a core sheet and metal foil layers as welded to the both surfaces of the core sheet. The core sheet is composed of a metal sheet of high thermal expansion as sandwiched between two metal sheets of low thermal expansion each having a number of through-holes in the direction of the thickness, and the three layers are laminated and integrated so that a part of the metal sheet of high thermal expansion is exposed out to the metal surfaces of low thermal expansion through the through-holes of the metal sheets of low thermal expansion. The metal foil layers each are made of a metal of high thermal expansion, which are same as or different from the metal of high thermal expansion of constituting the core sheet.

Abstract: A composite foil brazing material for joining ceramics to each other or to metal, which is made up of a core of Ti and outer layers of Ni or Ni alloy containing less than 80% of Cu, with the core and the composite foil having the respective sectional areas whose ratio is 5/10 to 9/10.