22k gold alloy compositions

Abstract

Novel 22 k gold alloys including silver, boron, cobalt and copper. The alloys meet modem jewelry fabrication techniques requirements and exhibit pleasing yellow color. They are stable under normal use and do not appreciably tarnish. They also have substantially no discoloring effect on the skin. These formulations possess work hardening properties consistent with gold alloys of lower karat while maintaining color properties consistent with traditional 22 k gold jewelry.

What is claimed is:  
     
         1 . A 22 K gold alloy comprising: 
 silver: 26% (and preferably 2-5%)    cobalt: 0.1 to 2% (and preferably 0.1-1%)    boron (optional) up to 0.5%    copper: 0.33% -8.40%.    
     
     
         2 . The composition of  claim 1  in which the silver content is less than 5%.  
     
     
         3 . The composition of  claim 1  in which the cobalt content is less than 2%.  
     
     
         4 . The composition of  claim 2  in which the cobalt content is less than 2%.  
     
     
         5 . A master alloy for combining with gold, comprising: 
 silver: 32-96%    cobalt: 1.6-32.00%    boron (optional) up to 8%    copper: 5.28-66.40%.    
     
     
         6 . A method of making a 22 K gold alloy comprising combining gold with the master alloy of  claim 5 .  
     
     
         7 . The alloy of  claim 1  in the form of a jewelry casting, a stamping, a wire or a sheet.  
     
     
         8 . The alloy of  claim 1  fabricated into a decorative article.  
     
     
         9 . The master alloy of  claim 5  for combining with gold to produce a 22 k alloy.  
     
     
         10 . The alloy of  claim 5  in which the silver content is less than 80%.  
     
     
         11 . The alloy of  claim 5  in which cobalt is less than 16.00%.  
     
     
         12 . The alloy of  claim 10  in which cobalt is less than 16.00%.