Method for manufacturing a biocompatible wire

Abstract

The disclosure relates to a method for manufacturing a biocompatible wire, a biocompatible wire comprising a biocompatible metallic material and a medical device comprising such wire. The method for manufacturing a biocompatible wire comprises providing a workpiece of a biocompatible metallic material, cold working the workpiece into a wire, and annealing the wire, wherein a cold work percentage is 97 to 99%, wherein the cold working is a drawing with a die reduction per pass ratio in a range of 6 to 40%, and wherein the annealing is done in a range of 850 to 1100° C.

1 . A biocompatible wire comprising a biocompatible metallic material, which is cold worked from a workpiece and annealed,
 wherein a cold work percentage is 97 to 99%,   wherein the cold working is a drawing with a die reduction per pass ratio in a range of 6 to 40 %, and   wherein the annealing is done in a range of 850 to 1100° C.   wherein the wire comprises grains with a mean grain size in a range of 20 to 1000 nm.   
     
     
         2 . The wire according to  claim 1 , wherein the wire has a yield strength in a range of 1300 to 1900 MPa. 
     
     
         3 . The wire according to  claim 1 , wherein the wire has an ultimate tensile strength in a range of 1700 to 2400 MPa. 
     
     
         4 . The wire according to  claim 1 , wherein the wire has an essentially uniform grain size distribution along a cross section of the wire. 
     
     
         5 . The wire according to  claim 1 , wherein the biocompatible metallic material is an alloy comprising the following components:
 Cr in a range from about 10 to about 30 wt. %;   Ni in a range from about 20 to about 50 wt. %;   Mo in a range from about 2 to about 20 wt. %;   Co in a range from about 10 to about 50 wt. %,   wherein the Cr, Ni, Mo and Co components are major constituents of the alloy with at least about 95 wt. % of the alloy being Cr, Ni, Mo and Co.   
     
     
         6 . The wire according to  claim 5 , wherein the biocompatible metallic material further comprises an additional material comprising at least one of a group of Silver, Platinum, Tantalum, Gold, Copper and alloys thereof. 
     
     
         7 . The wire according to  claim 6 , wherein the Cr, Ni, Mo and Co alloy forms a core and the additional material forms a shell around the core when the wire is seen in a cross section. 
     
     
         8 . The wire according to  claim 6 , wherein the additional material forms a core and the Cr, Ni, Mo and Co alloy forms a shell around the core when the wire is seen in a cross section. 
     
     
         9 . The wire according to  claim 1 , wherein the drawing is a full die drawing. 
     
     
         10 . The wire according to  claim 1 , wherein the drawing is done with a deformation factor in a range of 1.2 to 2.0 and a contact length between the workpiece and a drawing tool is in a range of 0.5 to 0.2 mm. 
     
     
         11 . The wire according to  claim 1 , wherein the drawing is done with a speed in a range of 15 to 150 m/min. 
     
     
         12 . The wire according to  claim 1 , wherein an initial diameter of the workpiece before drawing is in a range of 3 to 5 mm. 
     
     
         13 . The wire according to  claim 1 , wherein a diameter of the wire after drawing is in a range of 0.1 to 0.9 mm. 
     
     
         14 . The wire according to  claim 1 , wherein the annealing is done for 750 to 1500 seconds. 
     
     
         15 . The wire according to  claim 1 , wherein the annealing is followed by an additional drawing with a cold working percentage of 95 to 97%. 
     
     
         16 . A medical device, comprising a wire according to  claim 1 , as a lead.