Method of spark sintering electrically conductive particles onto a metallic substrate

Claim 1

A method of sintering metallic particles onto a metallic substrate of a material having an atomic size less than substantially the atomic size of the material constituting said particles, comprising the steps of juxtaposing said substrate with an electrode spaced therefrom, disposing a mass of said particles in contact with said substrate in the region of the gap between said electrode and said substrate and in continuous direct contact with said electrode, intermittently passing an impulsive electric current between said substrate and said electrode, and establishing the magnitude of said current and the compaction of said mass against said substrate to effect interrupted spark discharge among said particles and between said substrate and the particles of said mass proximal thereto, thereby bonding said particles to said substrate without melting of said mass.

Claim 2

A method of forming a body consisting of a continuous metallic layer and a sintered layer bonded to said metallic layer, comprising the steps of: disposing a mass of conductive spark-sinterable particles between a pair of electrodes in relatively light contacting relationship and in continuous direct contact with both said electrodes, at least one of said electrodes being metallic and spark sinterable to said mass while forming a substrate lightly juxtaposed with the mass of particles; and triggering impulsive and intermittent electric-current flow between said electrodes of a magnitude sufficient to effect a spark discharge between said one of said electrodes and particles of said mass proximal thereto and among at least some of said particles but less than that at which an arc is formed between said electrodes to fuse said particles together and concurrently to fuse said particles to said one of said electrodes without melting of said mass.