Non-magnetic noble alloy containing ruthenium, cobalt and chromium

Abstract

A noble alloy suitable for dental purposes that contains cobalt and chromium in addition to ruthenium and optionally gold and/or platinum group elements, and is non-magnetic is provided. In the alloy system cobalt-chromium-ruthenium-gallium it was found that gallium contents above about 10 weight percent may exhibit ferromagnetism upon slow cooling. Ferromagnetism is an undesirable feature for dental prosthesis. Reducing the gallium content below 10%, however, lowers the thermal expansion coefficient of the alloy.

1 . A dental alloy comprising:
 at least 25 wt. % of Ru;   from 15 to 35 wt. % Cr;   from 30 to 50 wt. % Co; and   at least 5 wt. % Ga;   wherein where the concentration of Ga is from 5 to 10 wt. % the alloy further contains a sufficient concentration up to 5 wt. % of at least one modifier selected from the group consisting Ge, Fe, B, In, Sn and Re such that the liquidus temperature of the alloy is below 1600 C.°;   wherein where the concentration of Ga is greater than 10 wt. %, the concentration of Co is at least 35 wt. %, the concentration of Cr is less than 25 wt. %, and the alloy further contains B in a concentration of up to 1 wt. %; and   wherein the alloy is non-magnetic.   
     
     
         2 . The dental alloy of  claim 1 , wherein the concentration of Ga is between 5 and 10 wt. % and the concentration of Ru is greater than 25 wt. % then the ratio of Co to Ga is 4 to 1 or less. 
     
     
         3 . The dental alloy of  claim 1 , wherein the concentration of Ga is between 5 and 10 wt. %, and wherein the alloy further contains at least 1 wt. % Re. 
     
     
         4 . The dental alloy of  claim 1 , wherein the concentration of Ga is between 5 and 10 wt. %, and wherein the total concentration of Ga and Re is at least 10 wt. %. 
     
     
         5 . 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. 
     
     
         6 . The dental alloy of  claim 1 , wherein the alloy has a composition selected from the group consisting of Co 40 Cr 27.5 Ru 25 Ga 7.5 , Co 38 Cr 30 Ru 25 Ga 7 , Co 41 Cr 25 Ru 25 Ga 8 Ge 1 , Co 35 Cr 25 Ru 30 Ga 10 , Co 40 Cr 25 Ru 25 Ga 5 Re 5 , and Co 37.5 Cr 30 Ru 25 Ga 7 B 0.5 . 
     
     
         7 . The dental alloy of  claim 1 , wherein the alloy has a thermal expansion coefficient within the range of from about 9 to about 18×10 −6 . 
     
     
         8 . The dental alloy of  claim 1 , wherein the concentration of Ga is greater than 10 wt. %, and wherein the concentration of B is from 0.15 to 0.55 wt. %. 
     
     
         9 . The dental alloy of  claim 1 , wherein the concentration of Ga is between 10 and 11.5 wt. %, the concentration of B is between 0.15 and 0.55 wt. %, the concentration of Co is at least 37 wt. %, and the concentration of Cr is between 22 and 25 wt. %. 
     
     
         10 . The dental alloy of  claim 1 , wherein the alloy has a composition selected from the group consisting of Co 40 Cr 24.35 Ru 25 Ga 10.5 B 0.15 , Co 40 Cr 23.35 Ru 25 Ga 11.5 B 0.15 , Co 40 Cr 23.95 Ru 25 Ga 10.5 B 0.55 , Co 37.5 Cr 22.95 Ru 25 Ga 11.5 B 0.35 , and Co 40 Cr 23.5 Ru 25 Ga 11 B 0.5 . 
     
     
         11 . The dental alloy of  claim 1 , wherein the concentration of Ga is between 5 and 10 wt. %, the concentration of Co is at least 35 wt. %, and the concentration of Cr is between 25 and 30 wt. %. 
     
     
         12 . The dental alloy of  claim 1 , wherein the alloy further comprises up to 10 wt. % of an additive selected from the group consisting of Si, W, Ta, Nb, Re, Mo and V. 
     
     
         13 . A dental alloy comprising:
 at least 25 wt. % of Ru;   from 15 to 35 wt. % Cr;   from 30 to 50 wt. % Co;   from 5 to 10 wt. % Ga;   further contains a sufficient concentration of up to 5 wt. % of at least one modifier selected from the group consisting Ge, Fe, B, In, Sn and Re such that the liquidus temperature of the alloy is below 1600 C.°;   wherein the ratio of Co to Ga is greater than 4 to 1; and   wherein the alloy is non-magnetic.   
     
     
         14 . A dental alloy comprising:
 at least 25 wt. % of Ru;   from 15 to 25 wt. % Cr;   from 35 to 50 wt. % Co;   at least 10 wt. % Ga;   wherein the alloy further contains B in a concentration of up to 1 wt. %; and   wherein the alloy is non-magnetic.   
     
     
         15 . A dental product comprising:
 a metallic body for dental application, said body being formed of a dental alloy comprising:
 at least 25 wt. % of Ru; 
 from 15 to 35 wt. % Cr; 
 from 30 to 50 wt. % Co; and 
 at least 5 wt. % Ga; 
 wherein where the concentration of Ga is from 5 to 10 wt. % the alloy further contains a sufficient concentration up to 5 wt. % of at least one modifier selected from the group consisting Ge, Fe, B, In, Sn and Re such that the liquidus temperature of the alloy is below 1600 C.°; 
 wherein where the concentration of Ga is greater than 10 wt. %, the concentration of Co is at least 35 wt. %, the concentration of Cr is less than 25 wt. %, and the alloy further contains B in a concentration of up to 1 wt. %; and 
 wherein the alloy is non-magnetic. 
   
     
     
         16 . The dental product of  claim 15 , wherein the concentration of Ga is between 5 and 10 wt. % and the concentration of Ru is greater than 25 wt. % then the ratio of Co to Ga is 4 to 1 or less. 
     
     
         17 . The dental product of  claim 16 , wherein the concentration of Ga is between 5 and 10 wt. %, and wherein the alloy further contains at least 1 wt. % Re. 
     
     
         18 . The dental product of  claim 15 , wherein the concentration of Ga is between 5 and 10 wt. % and wherein the total concentration of Ga and Re is at least 10 wt. %. 
     
     
         19 . The dental product of  claim 15 , 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. 
     
     
         20 . The dental product of  claim 15 , wherein the alloy has a composition selected from the group consisting of Co 40 Cr 27.5 Ru 25 Ga 7.5 , Co 38 Cr 30 Ru 25 Ga 7 , Co 41 Cr 25 Ru 25 Ga 8 Ge 1 , Co 35 Cr 25 Ru 30 Ga 10 , Co 40 Cr 25 Ru 25 Ga 5 Re 5 , and Co 37.5 Cr 30 Ru 25 Ga 7 B 0.5 . 
     
     
         21 . The dental product of  claim 15 , wherein the alloy has a thermal expansion coefficient within the range of from about 9 to about 18×10 −6 . 
     
     
         22 . The dental product of  claim 15 , wherein the concentration of Ga is greater than 10 wt. %, and wherein the concentration of B is between 0.15 and 0.55 wt. %. 
     
     
         23 . The dental product of  claim 15 , wherein the concentration of Ga is between 10 and 11.5 wt. %, the concentration of B is between 0.15 and 0.55 wt. %, the concentration of Co is at least 37 wt. %, and the concentration of Cr is between 22 and 25 wt. %. 
     
     
         24 . The dental product of  claim 15 , wherein the alloy further comprises up to 10 wt. % of an additive selected from the group consisting of Si, W, Ta, Nb, Re, Mo and V. 
     
     
         25 . The dental product of  claim 15 , wherein the alloy has a composition selected from the group consisting of Co 40 Cr 24.35 Ru 25 Ga 10.5 B 0.15 , Co 40 Cr 23.35 Ru 25 Ga 11.5 B 0.15 , Co 40 Cr 23.95 Ru 25 Ga 10.5 B 0.55 , Co 37.5 Cr 22.95 Ru 25 Ga 11.5 B 0.35 , and Co 40 Cr 23.5 Ru 25 Ga 11 B 0.5 . 
     
     
         26 . The dental product of  claim 15 , wherein the concentration of Ga is between 5 and 10 wt. %, the concentration of Co is at least 35 wt. %, and the concentration of Cr is between 25 and 30 wt. %. 
     
     
         27 . The dental product of  claim 15 , wherein where the concentration of Ga is from 5 to 10 wt. % then the ratio of Co to Ga is greater than 4 to 1.