Secondary metallization by glass displacement in ceramic substrate

Claim 1

A process for increasing the electrical conductance of a metallization on a ceramic substrate which comprises providing a ceramic substrate with an adherent electrically conductive refractory metal metallization wherein at least one portion of said metallization is exposed, said metallization being comprised of an intermixture of a continuous phase of refractory metal and a continuous phase of glass, said refractory metal ranging from about 25% by volume to about 65% by volume of said metallization, contacting said refractory metal at at least one exposed portion of said metallization with an intrusion metal selected from the group consisting of copper, nickel, tin, gold, iron, cobalt, and alloys thereof, heating the resulting structure to an infiltration temperature which is above the transition temperature of said glass and at which said intrusion metal is liquid but said refractory metal is solid thereby infiltrating said liquid intrusion metal into said metallization, at said infiltration temperature said liquid metal preferentially wetting said refractory metal displacing said glass with said intrusion metal, and allowing the resulting structure to cool thereby solidifying said infiltrated liquid intrusion metal in place, said solid infiltrated intrusion metal at least partly occupying the volume space originally occupied by said displaced glass and being in contact with said refractory metal phase, said process being carried out in an atmosphere which has no significant deleterious effect on said ceramic substrate, said refractory metal metallization and said intrusion metal.