Hardened cobalt based alloy jewelry and related methods

Abstract

Hardened cobalt alloys for forming jewelry, including finger rings as well as methods and processes for producing such alloys. In one illustrative embodiment, such an alloy can contain cobalt in an amount of from about 35 wt % to about 65 wt %, in combination with chromium in an amount of from about 16% wt to about 32 wt %, and molybdenum in an amount of from about 8 wt % to about 31 wt %. Aluminum, silicon, boron, titanium, and other hardness enhancing materials may also be present. Hot investment casting may be used to form items from the alloys, which may then be shaped or polished to a final form. Annular finger rings constructed from these materials may have a white appearance similar to white gold or platinum, may have increased resistance to scratching compared to traditional cobalt chromium rings, and may be easily be removed by cracking in an emergency situation.

1 . An alloy composition comprising:
 from 43 wt % to 50 wt % cobalt;   from 27 wt % to 32 wt % chromium;   from 12 wt % to 16 wt % molybdenum; and   from 0.5 wt % to 10 wt % of hardness enhancing materials;   wherein wt % is based on the total weight of the alloy composition; and   wherein the alloy composition, when configured with the dimensions of a finger ring, breaks upon application of a force less than 500 lbf to at least two points on the outside surface of the ring.   
     
     
         2 . The alloy composition of  claim 1 , wherein the alloy composition has a surface hardness from 50 HRC to 70 HRC. 
     
     
         3 . The alloy composition of  claim 1 , wherein the alloy composition, when configured with the dimensions of a finger ring, breaks upon application of a force less than 450 lbf to at least two points on the outside surface of the ring. 
     
     
         4 . The alloy composition of  claim 1 , wherein the alloy composition, when configured with the dimensions of a finger ring, breaks upon application of a force from 311 lbf to 463 lbf to at least two points on the outside surface of the ring. 
     
     
         5 . The alloy composition of  claim 1 , wherein the alloy composition comprises greater than 90 wt % of cobalt, chromium, molybdenum, and the hardness enhancing materials combined, wherein wt % is based on the total weight of the alloy composition. 
     
     
         6 . The alloy composition of  claim 1 , wherein,
 the hardness enhancing materials comprise nickel; and   release of the nickel from the alloy composition is less than 0.01 μg/cm 2 /week as determined using spectrometry.   
     
     
         7 . The alloy composition of  claim 1 , wherein the hardness enhancing materials comprise carbon, nickel, iron, manganese and silicon. 
     
     
         8 . The alloy composition of  claim 1 , wherein the hardness enhancing materials comprise aluminum, silicon boron, titanium, iron, nickel, zirconium, cerium, lanthanum, carbon, manganese, or a combination of any of the foregoing. 
     
     
         9 . The alloy composition of  claim 1 , wherein the hardness enhancing materials comprise up to but not more than 6 wt % iron, wherein wt % is based on the total weight of the alloy composition. 
     
     
         10 . The alloy composition of  claim 1 , wherein the hardness enhancing materials comprise up to but not more than 3 wt % each of carbon, nickel, and manganese, wherein wt % is based on the total weight of the alloy composition. 
     
     
         11 . An alloy composition comprising:
 from 43 wt % to 50 wt % cobalt;   from 27 wt % to 32 wt % chromium;   from 12 wt % to 16 wt % molybdenum; and   from 0.5 wt % to 10 wt % of hardness enhancing materials;   wherein wt % is based on the total weight of the alloy composition;   wherein the alloy composition, when configured with the dimensions of a finger ring, breaks upon application of a force less than 500 lbf to at least two points on the outside surface of the ring;   wherein the alloy composition has a surface hardness from 50 HRC to 70 HRC;   wherein the hardness enhancing materials comprise nickel; and release of the nickel from the alloy composition is less than 0.01 μg/cm 2 /week as determined using spectrometry; and   wherein the hardness enhancing materials comprise carbon, nickel, iron, manganese and silicon.   
     
     
         12 . An alloy composition comprising:
 from 35 wt % to 65 wt % cobalt;   from 16 wt % to 32 wt % chromium;   from 8 wt % to 31 wt % molybdenum; and   from 0.5 wt % to 10 wt % of hardness enhancing materials;   wherein wt % is based on the total weight of the alloy composition; and   wherein the alloy composition, when configured with the dimensions of a finger ring, breaks upon application of a force less than 500 lbf to at least two points on the outside surface of the ring.   
     
     
         13 . The alloy composition of  claim 12 , wherein the alloy composition has a surface hardness from 50 HRC to 70 HRC. 
     
     
         14 . The alloy composition of  claim 12 , wherein the alloy composition, when configured with the dimensions of a finger ring, breaks upon application of a force less than 450 lbf to at least two points on the outside surface of the ring. 
     
     
         15 . The alloy composition of  claim 12 , wherein the alloy composition, when configured with the dimensions of a finger ring, breaks upon application of a force from 311 lbf to 463 lbf to at least two points on the outside surface of the ring. 
     
     
         16 . The alloy composition of  claim 12 , wherein the alloy composition comprises greater than 90 wt % of cobalt, chromium, molybdenum, and the hardness enhancing materials combined, wherein wt % is based on the total weight of the alloy composition. 
     
     
         17 . The alloy composition of  claim 12 , wherein,
 the hardness enhancing materials comprise nickel; and   release of the nickel from the alloy composition is less than 0.01 μg/cm 2 /week as determined using spectrometry.   
     
     
         18 . The alloy composition of  claim 12 , wherein the hardness enhancing materials comprise carbon, nickel, iron, manganese and silicon. 
     
     
         19 . The alloy composition of  claim 12 , wherein the hardness enhancing materials comprise up to but not more than 6 wt % iron, wherein wt % is based on the total weight of the alloy composition. 
     
     
         20 . The alloy composition of  claim 12 , wherein the hardness enhancing material comprise up to but not more than 3 wt % each of carbon, nickel, and manganese, wherein wt % is based on the total weight of the alloy composition.