An insulated, corrosion-resistant heart pacer is described which incorporates a novel tantalum output means, said output means having disposed on at least the exterior surfaces thereof an anodically-formed substantially continuous Ta.sub.2 O.sub.5 insulating layer. The output means of the pacer or other medical electronic device comprises a tantalum centerpin disposed through a hermetically sealed titanium case, which centerpin is welded to a tantalum feed wire, the combination providing a device in which the Ta.sub.2 O.sub.5 insulating layer reduces the electrical leakage from the tantalum conductor to the titanium case, and whereby the insulating layer disposed thereon further protects the pacer from electrolysis and electrochemical corrosion. An alternate embodiment of the present invention provides tantalum conduit means for electrically connecting an energy source to logic circuitry which is disposed within a hermetically sealed titanium case. Finally, a method is provided for producing and utilizing tantalum, titanium, aluminum, hafnium, niobium, and like metals, which comprises the step of forming a continuous oxidation layer of components of such metals, which method of forming includes the steps of immersing the output means in an electrolytic solution and applying a positive voltage to the tantalum or like material to aniodically form a Ta.sub.2 O.sub.5 or corresponding insulating layer thereon. As a result, a corrosion resistant insulated heart pacer is provided having better insulation against the effects of electrolysis and electrochemical corrosion, as well as one in which discharge of the energy source is minimized.