A method for manufacturing a feedthrough dielectric body for an active implantable medical device includes the steps of first forming a ceramic reinforced metal composite (CRMC) paste by mixing platinum with a ceramic material to form a CRMC material, subjecting the CRMC material to a first sintering step to thereby form a sintered CRMC material, ball-milling or grinding the sintered CRMC material to form a powdered CRMC material; and then mixing the powdered CRMC material with a solvent to form the CRMC paste. The method further includes forming an alumina ceramic body in a green state, forming at least one via hole through the alumina ceramic body, filling the via hole with the CRMC paste, drying the ceramic body including the CRMC paste to form a first CRMC material filling the via hole, forming a second via hole through the first CRMC material, providing a metal core in the second via hole, and subjecting the ceramic body including the first CRMC material and the metal core to a second sintering step to thereby form the dielectric body. The dielectric body is then sealed in a ferrule opening to form a feedthrough.