Abstract: Catheters and other medical devices include plural layers of metals applied to the outer surfaces, which tend to close minuscule cracks through which corrosion may attack the underlying support. In some avatars, the initial layer of material is preferably silver, applied following specific preparation steps. In other embodiments, succeeding layers of metal completely cover the initial layer, and are also of silver. The succeeding layers are deposited after deposition of the prior layer, and tend to reduce the incidence of microscopic pores or cracks and are less prone to delamination. The succeeding layers are preferably of mutually different metals between layers. In a particular avatar, in which the exposed metals are oligodynamic silver and more noble platinum, the exposed silver layer lies over a portion of the platinum layer, to thereby prevent corrosion of the silver layer from disconnecting portions of the silver layer.