Cemented carbide material and method of making same

Abstract

A cemented carbide material comprises WC, between around 3 to around 10 wt. % Co and between around 0.5 to around 8 wt. % Re. The equivalent total carbon (ETC) content of the cemented carbide material with respect to WC is between around 6.3 wt. % to around 6.9 wt. % and the cemented carbide material is substantially free of eta-phase and free carbon. There is also disclosed a method of producing such a material and use of such a material.

1 . A cemented carbide material comprising WC, Co and Re, wherein:
 the cemented carbide material comprises between around 3 to around 10 wt. % Co and between around 0.5 to around 8 wt. % Re;   the equivalent total carbon (ETC) content of the cemented carbide material with respect to WC being between around 6.3 wt. % to around 6.9 wt. %   the cemented carbide material being substantially free of eta-phase and free carbon.   
     
     
         2 . The cemented carbide material of  claim 1 , wherein the cemented carbide material comprises between around 0.5 to around 6 wt % Re. 
     
     
         3 . The cemented carbide material of  claim 1 , wherein the WC in the material has a mean grain size less than around 0.6 μm. 
     
     
         4 . The cemented carbide material of  claim 1 , wherein the cemented carbide material has a magnetic saturation of at least around 40 percent to around 80 percent of the magnetic saturation of nominally pure Co. 
     
     
         5 . The cemented carbide material of  claim 1 , wherein the carbide phase is formed of carbide grains having a mean grain size of at least around 0.1 μm to at most around 10 μm. 
     
     
         6 . The cemented carbide material of  claim 1 , wherein the cemented carbide material has an associated magnetic coercive force varying from around 2 kA/m to around 70 kA/m. 
     
     
         7 . The cemented carbide material of  claim 1 , further comprising a carbide of one or more metals in form of the second carbide phase, or dissolved in a binder phase in the material, said one or more metals comprising Ti, V, Cr, Mn, Zr, Nb, Mo, Hf and/or Ta. 
     
     
         8 . The cemented carbide material of  claim 1 , wherein the material comprises a binder phase having one or more residual compressive stresses. 
     
     
         9 . The cemented carbide material of  claim 8 , wherein the binder phase comprises a binder material, the binder material comprising or a solid solution of Re, carbon and W and one of more of Fe, Co, and Ni. 
     
     
         10 . The cemented carbide material as claimed in  claim 1 , wherein the carbide phase comprises WC; and the cemented carbide material has a coercive force Hc in kA/m as a function of the WC mean grain size D wc  in μm determined on the basis of EBSD images of the carbide microstructure equal to or less than values given by the equation:
     Hc= 10× D   wc   −0.62  
 
 
     
     
         11 . The cemented carbide material as claimed in  claim 1 , wherein the Young's Modulus of said material is above around 700 GPa. 
     
     
         12 . The cemented carbide material as claimed in  claim 1 , wherein the hardness-toughness coefficient calculated by multiplying the Vickers hardness in GPa and fracture toughness in MPa m 1/2  is above around 190. 
     
     
         13 . The cemented carbide material as claimed in  claim 1 , wherein the material comprises at least about 0.01 weight percent and at most about 2 weight percent of one or more of Ru, Rh, Pd, Os, Ir and Pt 
     
     
         14 . A polycrystalline superhard construction comprising:
 a substrate comprising the cemented carbide material of  claim 1 ; and   a body of polycrystalline superhard material bonded to the substrate along an interface.   
     
     
         15 . The polycrystalline superhard construction of  claim 20 , wherein the body of polycrystalline superhard material comprises polycrystalline diamond (PCD) material or PCBN. 
     
     
         16 . A method of producing the cemented carbide material of  claim 1 , the method comprising:
 milling a cemented carbide mixture containing WC and carbon with Re, Co, Ni and/or Fe and optionally grain growth inhibitors comprising one or more of V, Cr, Ta, Ti, Mo, Zr, Nb and Hf or a carbide thereof;   pressing the cemented carbide article from the mixture;   sintering the article at a temperature of above around 1450° C. in vacuum for between around 1 to 10 minutes and a pressure of Ar (HIP) for around 5 to 120 minutes; and   cooling the article from sintering the temperature to approximately 1300 degrees Centigrade (° C.); wherein the step of cooling the article comprises:   cooling the article in an atmosphere comprising one or more of an inert gas, nitrogen, hydrogen or a mixture thereof, at a cooling rate of approximately 0.2 to 2 degrees per minute; or   cooling the article in a vacuum at a cooling rate of approximately 0.2 to 2 degrees per minute.   
     
     
         17 . A method of recycling the cemented carbide material of  claim 1 , the method comprising melting the carbide material in a protective atmosphere with liquid Zn, evaporating the Zn to form a resultant product; and milling the resulting product to recover Re from the product. 
     
     
         18 . A method of recycling the cemented carbide material of  claim 1 , the method comprising subjecting the cemented carbide material to an acid leaching mixture to remove the binder phase from the cemented carbide material; and chemically recovering Co and Re from the removed binder phase. 
     
     
         19 . A method of recycling the cemented carbide material of  claim 1 , the method comprising oxidation of the cemented carbide material to dissolve the carbide, Re and Co, and recovering the Re. 
     
     
         20 . Use of a cemented carbide material in a high-pressure component for synthesis of diamond or c-BN, or in fabrication of polycrystalline diamond or c-BN operating at a pressure of above 5 GPa and a temperature of above 1100° C., wherein the cemented carbide material comprises:
 a carbide of one or more metals in form of the second carbide phase, or dissolved in a binder phase in the material, said one or more metals comprising Ti, V, Cr, Mn, Zr, Nb, Mo, Hf and/or Ta; 
 between around 0.5 to around 8 wt. % Re and between around 3 to around 10 wt. % Co; 
 the equivalent total carbon (ETC) content of the cemented carbide material with respect to WC being between around 6.3 wt. % to around 6.9 wt. % 
 the cemented carbide material being substantially free of eta-phase and free carbon.