Process and material solution to reduce metal ion release for implantable medical device application
AssigneeMedtronic, Inc.
InventorsAlan Shi, Bernard Li
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Abstract
The invention describes a method and compositions where the presence of cobalt and or nickel have been depleted from the surface layer(s) of a cobalt, chromium, nickel containing alloy.
Claims22
A treated alloy composition comprising cobalt, nickel, molybdenum and chromium, wherein the alloy surface has increased concentrations of molybdenum and chromium within at least the first 2 nm of the depth of the surface, wherein the alloy surface concentration of molybdenum is from about 2.2 atomic percent to about 3.9 atomic percent and the concentration of chromium is from about 10.4 atomic percent to about 17.5 atomic percent.
A treated alloy composition comprising cobalt, nickel, molybdenum and chromium, wherein the alloy surface has increased concentrations of molybdenum and chromium, wherein the alloy surface concentration of molybdenum is from about 2.2 atomic percent to about 3.9 atomic percent and the concentration of chromium is from about 10.4 atomic percent to about 17.5 atomic percent, and wherein the alloy releases less than 1 ng/mm2 of cobalt or nickel over a 16 week period at 37° C. in an aqueous nitric acid solution at a pH of 2.2.
Dependencies are inferred from the claim text.