Non-magnetic cobalt-palladium dental alloy

Abstract

A non-magnetic cobalt based “noble” metal dental alloy is provided. The alloy generally contains at least 25 wt. % palladium, from 15 to 30 wt. % chromium and a balance of cobalt, where to ensure the alloy is non-magnetic the concentration of chromium in the alloy is at least 20 wt.%, or if the concentration of chromium is less than 20 wt. % the combined concentration of chromium, molybdenum, tungsten, niobium, tantalum vanadium and rhenium is greater than 20 wt. %.

What is claimed is: 
     
         1 . A non-magnetic dental alloy comprising cobalt and further comprising:
 at least 25 wt. % of a first material selected from the group consisting of palladium, iridium, osmium, ruthenium, platinum, rhodium, gold, and combinations thereof;   0 to 20 wt. % of a second material selected from the group consisting of molybdenum, tungsten, tantalum, niobium, rhenium, and combinations thereof; and   15 wt. % to 35 wt. % chromium;   wherein palladium comprises a majority of the first material; and   wherein the dental alloy is non-magnetic.   
     
     
         2 . The dental alloy of  claim 1 , wherein the concentration of the second material is dependent on the concentration of chromium in accordance with the following:
 where chromium is at least 20 wt. % then the second material is from 0 to 20 wt. %, and where chromium is less than 20 wt. % then the sum of chromium and the second material is greater than 20 wt. %.   
     
     
         3 . The dental alloy of  claim 1 , wherein palladium is at least 24 wt. %. 
     
     
         4 . The dental alloy of  claim 1 , comprising 30 wt. % to 60 wt. % cobalt. 
     
     
         5 . The dental alloy of  claim 1 , wherein the alloy further comprises up to about 5 wt. % of at least one additive material selected from the group consisting of aluminum, boron, cerium, gallium, germanium, silicon, and combinations thereof 
     
     
         6 . The dental alloy of  claim 5 , wherein the at least one additive material is selected from the group consisting of up to 2 wt. % gallium, up to 3 wt. % silicon, up to 1 wt. % boron, up to 3 wt. % aluminum, up to 3 wt. % germanium, up to 1 wt. % cerium, and combinations thereof. 
     
     
         7 . The dental alloy of  claim 1 , wherein the alloy further comprises less than 5 wt. % of at least one trace additive selected from the group consisting of copper, nickel and iron. 
     
     
         8 . The dental alloy of  claim 1 , wherein the sum of chromium and the first and second materials is from 45 wt. % to 70 wt. %. 
     
     
         9 . The dental alloy of  claim 1 , wherein the alloy has a thermal expansion coefficient from about 13 to about 18×10 −6 . 
     
     
         10 . The dental alloy of  claim 1 , wherein the alloy has a liquidus temperature of below about 1350° C. 
     
     
         11 . A dental product comprising:
 a body for dental application, said body being formed of a non-magnetic dental alloy comprising cobalt and further comprising:
 at least 25 wt. % of a first material selected from the group consisting of palladium, iridium, osmium, ruthenium, platinum, rhodium, gold, and combinations thereof; 
 0 to 20 wt. % of a second material selected from the group consisting of molybdenum, tungsten, tantalum, niobium, rhenium, and combinations thereof; and 
 15 wt. % to 35 wt. % chromium; 
   wherein palladium comprises a majority of the first material; and   wherein the dental alloy is non-magnetic.   
     
     
         12 . The dental product of  claim 11 , wherein the concentration of the second material is dependent on the concentration of chromium in accordance with the following:
 where chromium is at least 20 wt. % then the second material is from 0 to 20 wt. %, and where chromium is less than 20 wt. % then the sum of chromium and the second material is greater than 20 wt. %.   
     
     
         13 . The dental product of  claim 11 , wherein palladium is at least 24 wt. %. 
     
     
         14 . The dental alloy of  claim 11 , comprising 30 wt. % to 60 wt. % cobalt. 
     
     
         15 . The dental product of  claim 11 , wherein the alloy further comprises up to about 5 wt. % of at least one additive material selected from the group consisting of aluminum, boron, cerium, gallium, germanium, silicon, and combinations thereof. 
     
     
         16 . The dental product of  claim 15 , wherein the at least one additive material is selected from the group consisting of up to 2 wt. % gallium, up to 3 wt. % silicon, up to 1 wt. % boron, up to 3 wt. % aluminum, up to 3 wt. % germanium, up to 1 wt. % cerium, and combinations thereof. 
     
     
         17 . The dental product of  claim 11 , wherein the alloy further comprises less than 5 wt. % of at least one trace additive selected from the group consisting of copper, nickel and iron. 
     
     
         18 . The dental product of  claim 11 , where the sum of chromium and the first and second materials is from 45 wt. % to 70 wt. %. 
     
     
         19 . The dental product of  claim 11 , wherein the alloy has a thermal expansion coefficient of from about 13 to about 18×10 −6 . 
     
     
         20 . The dental product of  claim 11 , wherein the alloy has a liquidus temperature of below about 1350° C.