Gradient polycrystalline cubic boron nitride materials and tools incorporating such materials

Abstract

Gradient polycrystalline cubic boron nitride (PCBN) materials are provided as well as tools incorporating such materials.

1 . A polycrystalline cubic boron nitride material comprising: 
 a first layer of polycrystalline cubic boron nitride formed from cubic boron nitride grains; and    a second layer of polycrystalline cubic boron nitride bonded to the first layer, wherein the second layer is formed from cubic boron nitride grains which are coarser than the cubic boron nitride grains forming the first layer.    
     
     
         2 . A material as recited in  claim 1  further comprising a third layer of polycrystalline cubic boron nitride formed from cubic boron nitride grains which are finer than the grains of cubic boron nitride forming the second layer.  
     
     
         3 . A material as recited in  claim 2  wherein the second layer is sandwiched between the first and third layers.  
     
     
         4 . A material as recited in  claim 3  wherein the first and third layers are made of the same material.  
     
     
         5 . A material as recited in  claim 3  wherein the first and third layers comprise the same type of cubic boron nitride and the same second phase compositions.  
     
     
         6 . A material as recited in  claim 5  wherein the first and third layers comprise a ceramic binder phase.  
     
     
         7 . A material as recited in  claim 1  further comprising a third layer of polycrystalline cubic boron nitride formed from cubic boron nitride grains which are coarser than the grains of cubic boron nitride forming the first layer.  
     
     
         8 . A material as recited in  claim 7  wherein the first layer is sandwiched between the second and third layers.  
     
     
         9 . A material as recited in  claim 8  wherein the second and third layers are made of the same material.  
     
     
         10 . A material as recited in  claim 8  wherein the second and third layers comprise the same type of cubic boron nitride and the same second phase compositions.  
     
     
         11 . A material as recited in  claim 8  wherein the second and third layers comprise a ceramic binder phase.  
     
     
         12 . A material as recited in  claim 11  wherein the second and third layers each comprise about 50% to about 80% by volume cubic boron nitride with the balance comprising a metallic phase and the ceramic phase.  
     
     
         13 . A material as recited in  claim 12  wherein the metallic phase comprises a material selected from the group of materials consisting of Co, Ni, Fe, and Wc.  
     
     
         14 . A material as recited in  claim 12  wherein the ceramic phase comprises at least one of a carbide and a nitride.  
     
     
         15 . A material as recited in  claim 14  wherein said carbide and nitride are selected from the group consisting of AIN, TiN, TiC, TiCN and carbides or nitrides of the IVB, VB and VIB elements of the Periodic Table of Elements, and combinations thereof.  
     
     
         16 . A material as recited in  claim 12  wherein the second and third layers further comprise an oxide phase.  
     
     
         17 . A material as recited in  claim 12  wherein the oxide phase comprises a composition consisting of Al 2 O 3 , SiO 2  and TiO 2 .  
     
     
         18 . A material as recited in  claim 12  wherein the first layer comprises about 60% to about 95% by volume cubic boron nitride.  
     
     
         19 . A material as recited in  claim 1  wherein each layer comprises cubic boron nitride in the range of about 50% to about 95% by volume, a metallic phase and a ceramic phase.  
     
     
         20 . A material as recited in  claim 19  wherein the metallic phase comprises a material selected from the group of materials consisting of Co, Ni, Fe, and Wc.  
     
     
         21 . A material as recited in  claim 19  wherein the ceramic phase comprises at least one of a carbide and a nitride.  
     
     
         22 . A material as recited in  claim 21  wherein said carbide and nitride are selected from the group consisting of AIN, TiN; TiC, TiCN and carbides or nitrides of the IVB, VB and VIB elements of the Periodic Table of Elements, and combinations thereof.  
     
     
         23 . A material as recited in  claim 19  wherein each layer further comprises an oxide phase.  
     
     
         24 . A material as recited in  claim 23  wherein the oxide phase comprises a composition consisting of Al 2 O 3 , SiO 2  and TiO 2 .  
     
     
         25 . A material as recited in  claim 1  wherein the first layer is formed from cubic boron nitride grains having a size in the range of less than 1 micron to about 10 microns.  
     
     
         26 . A material as recited in  claim 1  wherein the second layer is formed from cubic boron nitride grains having a size in the range of about 2 microns to about 30 microns.  
     
     
         27 . A material as recited in  claim 1  wherein at least one of the layers comprises a ceramic binder phase.  
     
     
         28 . A material as recited in  claim 1  further comprising a carbide substrate bonded to at least one of said first and second layers  
     
     
         29 . A polycrystalline cubic boron nitride material comprising: 
 a first layer of polycrystalline cubic boron nitride formed from cubic boron nitride grains and a second phase material; and    a second layer of polycrystalline cubic boron nitride bonded to the first layer, wherein the second layer is formed from cubic boron nitride grains having the same size as the grains forming the first layer, and wherein the second layer comprises a second phase material different from the second phase material of the first layer.    
     
     
         30 . A material as recited in  claim 29  wherein the first layer comprises from about 50% to about 80% by volume cubic boron nitride, a binder phase and a ceramic phase, wherein at least one of said binder and ceramic phases forms said second phase of said first layer.  
     
     
         31 . A material as recited in  claim 30  wherein the binder phase comprises a material selected from the group of materials consisting of Co, Ni, Fe, and Wc.  
     
     
         32 . A material as recited in  claim 30  wherein the ceramic phase comprises at least one of a carbide and a nitride.  
     
     
         33 . A material as recited in  claim 32  wherein said carbide and nitride are selected from the group consisting of AIN, TiN, TiC, TiCN and carbides or nitrides of the IVB, VB and VIB elements of the Periodic Table of Elements, and combinations thereof.  
     
     
         34 . A material as recited in  claim 30  wherein the second layer comprises from about 80% to about 95% by volume cubic boron nitride and a metallic second phase.  
     
     
         35 . A material as recited in  claim 29  wherein the second layer comprises from about 80% to about 95% by volume cubic boron nitride and a metallic second phase.  
     
     
         36 . A material as recited in  claim 35  wherein the metallic phase comprises a material selected from the group of materials consisting of Co, Ni, Fe, and Wc.  
     
     
         37 . A material as recited in  claim 29  wherein sizes of the cubic boron nitride grains forming each of the first and the second layers range from about 1 micron to about 10 microns.  
     
     
         38 . A material as recited in  claim 29  further comprising a carbide substrate bonded to at least one of said first and second layers