Polycrystalline diamond material

Abstract

A polycrystalline diamond material comprises a mass of diamond particles or grains exhibiting inter-granular bonding and a binder material comprising a non-metallic catalyst material for diamond, the non-metallic catalyst material for diamond being a metal oxoanion, the oxoanion being selected from the group comprising molybdates, tungstates, vanadates, phosphates and mixtures thereof.

1 . A polycrystalline diamond material comprising a mass of diamond particles or grains exhibiting inter-granular bonding and a binder material comprising a non-metallic catalyst material for diamond, the non-metallic catalyst material for diamond being a metal oxoanion, the oxoanion being selected from the group comprising molybdates, tungstates, vanadates, phosphates and mixtures thereof. 
     
     
         2 . A polycrystalline diamond material according to  claim 1 , wherein the metal oxoanion is selected from the group of compounds of the general formula A(M x O y ) z  or AB(M x O y ) z , where A and B are alkali metals, alkali earth metals, transition metals, lanthanides, actinides, or monovalent, divalent or trivalent metals, M is tungsten, molybdenum, vanadium or phosphorous, and 0.67≦x≦4, 3≦y≦12, and 1≦z≦3. 
     
     
         3 . A polycrystalline diamond material according to  claim 1 , wherein the metal oxoanion is selected from the group comprising sodium molybdate, cobalt molybdate, zirconium tungstate, potassium vanadate, KBi(WO 4 ) 2 , La 4 Cu 3 MoO 12 , ZrMo 2 O 8 , HfW 2 O 8 , La 2 Mo 3 O 12 , Eu 2 Mo 3 O 12 , Sc 0.67 WO 4 , Eu 0.67 MoO 4 , Zr 2 (WO 4 )(PO 4 ) 2  and LnAg(WO 4 )(MoO 4 ). 
     
     
         4 . A polycrystalline diamond material according to  claim 1 , wherein the metal oxoanion is sodium molybdate. 
     
     
         5 . A polycrystalline diamond material according to  claim 1 , wherein the diamond particles have an average particle or grain size of from about 10 nanometres to about 50 microns. 
     
     
         6 . A polycrystalline diamond material according to  claim 1 , wherein the diamond content of the polycrystalline diamond material is at least 80 percent and at most 98 percent of the volume of the polycrystalline diamond material. 
     
     
         7 . A polycrystalline diamond material according to  claim 1 , wherein the polycrystalline diamond material comprises at most 20 volume percent of the non-metallic catalyst material for diamond. 
     
     
         8 . A method for making polycrystalline diamond material, the method including providing a mass of diamond particles or grains, contacting the diamond particles or grains with a binder material comprising a non-metallic catalyst material for diamond, the non-metallic catalyst material for diamond being a metal oxoanion, the oxoanion being selected from the group comprising the molybdates, tungstates, vanadates, phosphates and mixtures thereof, consolidating the diamond particles or grains and binder material to form a green body, and subjecting the green body to a temperature and pressure at which diamond is thermodynamically stable, sintering and forming polycrystalline diamond material. 
     
     
         9 . A method according to  claim 8 , wherein the metal oxoanion is selected from the group of compounds of the general formula A(M x O y ) z  or AB(M x O y ) z , where A and B are alkali metals, alkali earth metals, transition metals, lanthanides, actinides, or monovalent, divalent or trivalent metals, M is tungsten, molybdenum, vanadium or phosphorous, and 0.67≦x≦4, 3≦y≦12, and 1≦z≦3. 
     
     
         10 . A method according to  claim 8 , wherein the metal oxoanion is selected from the group comprising sodium molybdate, cobalt molybdate, zirconium tungstate, potassium vanadate, KBi(WO 4 ) 2 , La 4 Cu 3 MoO 12 , ZrMo 2 O 8 , HfW 2 O 8 , La 2 Mo 3 O 12 , Eu 2 Mo 3 O 12 , Sc 0.67 WO 4 , Eu 0.67 MoO 4 , Zr 2 (WO 4 )(PO 4 ) 2  and LnAg(WO 4 )(MoO 4 ). 
     
     
         11 . A method according to  claim 8 , wherein the metal oxoanion is sodium molybdate. 
     
     
         12 . A method according to  claim 8 , wherein the method includes subjecting the green body in the presence of the non-metallic catalyst material for diamond to a pressure and temperature at which diamond is more thermodynamically stable than graphite. 
     
     
         13 . A method according to  claim 12 , wherein the pressure is at least about 6.8 GPa and the temperature is at least about 1500 degrees centigrade. 
     
     
         14 . A method according to  claim 8 , wherein the formed polycrystalline diamond material defines an attachment surface, the method including reducing non-metallic catalyst material for diamond adjacent the attachment surface to its metallic form and attaching a substrate or other supporting material to the attachment surface of the polycrystalline diamond material. 
     
     
         15 . A wear element comprising a polycrystalline diamond material according to  claim 1 .