Process for electropolishing a device made from cobalt-chromium

摘要

The invention is directed to an electropolishing solution for products or devices made from at least in part a cobalt-chromium alloy. The invention is particularly suitable for medical devices or intravascular stents made at least in part of cobalt-chromium. More particularly, the electropolishing process of the invention is particularly suited for use on implantable medical devices, such as stents, due to the biocompatibility of cobalt-chromium alloys. The invention is directed to an improved stent formed from a cobalt-chromium alloy, that possesses an ultrasmooth shiny surface. This invention is also directed to a method of electropolishing such a stent using an acidic electrolytic solution comprising a mixture of 6 parts of about 98% sulfuric acid (H₂SO₄), 1 part of about 37% hydrochloric acid (HCl) and 1 part by of about 85% concentrated phosphoric acid (H₃PO₄) to produce an exceptionally smooth surface.