Platinum/palladium alloy

Abstract

This invention relates to a platinum alloy for use in fine jewelry as an alternative to traditional grades of platinum or white gold. This alloy affords a much whiter color and a higher level of hardness to maintain the surface over an extended period of time that a piece of jewelry may be worn (sometimes many years). Platinum alloys have many desirable working properties, which this alloy equals or surpasses.

1 . A platinum alloy consisting essentially of 45 to 55 percent platinum and 55 to 45 percent palladium in which the ASTM yellow index is less than 12 and a penetration hardness is greater than 125 VPN.  
     
     
         2 . The alloy of  claim 1  wherein the platinum is 50 to 50.5 percent and the palladium is at 50 to 49.5 percent.  
     
     
         3 . The alloy of  claim 2  wherein the penetration hardness is greater than 150 VPN.  
     
     
         4 . The alloy of  claim 2  which additionally has an elongation to break of greater than 20 percent.  
     
     
         5 . The alloy of  claim 2  which has a tensile strength of greater than 12 TSI.  
     
     
         6 . An article of jewelry made from the alloy of  claim 1 .  
     
     
         7 . A platinum alloy containing 50.5 percent platinum and 49.5 percent palladium.