Abstract: A feedthrough filter capacitor assembly is described. The feedthrough filter capacitor assembly comprises an outer ferrule hermetically sealed to an insulator of a dielectric material seated within the ferrule. The insulative material is also hermetically sealed to at least one lead wire. Instead of being made of platinum or platinum/iridium, the lead wire comprises a core of a non-noble metal supporting a functionally graded coating. The metal core has an inner layer of the same the non-noble metal of the core and an outer layer of a noble metal. A gradient transition zone exists between the non-noble metal and the outer noble metal. Consequently, lead wires having all the beneficial attributes of platinum and platinum/iridium wire can be built into hermetic feedthroughs, but at a significantly reduced cost.