Polycrystalline Cubic Boron Nitride (PcBN) Body Made With Distinct Layers of PcBN

Abstract

A polycrystalline cubic boron nitride (PcBN) is fabricated using a process of overlaying layers of cubic boron nitride (cBN) powder, where the layers have cBN mixed with various concentrations of a ceramic. The process of fabricating the PcBN includes depositing, in a refractory capsule, a carbide, a cubic boron nitride (cBN), and a mixture of cBN and a ceramic, then applying a high pressure and high temperature (HPHT) to the content of the refractory capsule. During the depositing step of the process, the concentration of cBN in the mixture of the cBN and ceramic is lower than the concentration of cBN that is in the layer below it. Upon applying HPHT, the carbide first diffuses across the cBN layer, and then diffuses across the layer with the mixture of the cBN and ceramic. After HPHT ends and the content of the refractory capsule cools, the process yields a PcBN having layers with various concentrations of cBN, and at least one cBN layer with a ceramic material.

We claim: 
     
         1 . A process of fabricating a polycrystalline cubic boron nitride (PcBN) cutting tool, comprising:
 depositing:
 a first amount of a substrate; 
 a second amount of at least a cubic boron nitride (cBN); 
 a third amount of a mixture of cBN and ceramic; and 
   applying a high pressure and high temperature (HPHT).   
     
     
         2 . The process of  claim 1 , wherein the substrate comprises at least one of a metal and silicon. 
     
     
         3 . The process of  claim 1 , wherein the depositing is into a refractory capsule formed from a foil sheet or wrap of tantalum (Ta), molybdenum (Mo), or a grade IV-VI transition metal. 
     
     
         4 . The process of  claim 1 , wherein the substrate includes carbide. 
     
     
         5 . The process of  claim 1 , wherein the ceramic includes at least one from a group consisting of: TiN, Al 2 O 3 , AlN, TiC, TiCN, ZrN, ZrO 2 , and HfO 2 . 
     
     
         6 . The process of  claim 3 , wherein the refractory capsule includes: (1) the substrate, (2) the cBN, and (3) the mixture of cBN powder and ceramic. 
     
     
         7 . The process of  claim 6 , wherein the ceramic includes at least one from a group consisting of: TiN, Al 2 O 3 , AlN, Ti 2 AlN, TiC, TiCN, ZrN, ZrO 2 , and HfO 2 . 
     
     
         8 . The process of  claim 1 , further comprising the step of ending application of HPHT. 
     
     
         9 . The process of  claim 1 , wherein a first concentration of cBN in the third amount is lower than a second concentration of cBN in the second amount. 
     
     
         10 . The process of  claim 4 , wherein upon applying the HPHT, carbide of the substrate first diffuses across the second amount of at least the cBN, and then diffuses across the third amount of the mixture of the cBN and ceramic. 
     
     
         11 . The process of  claim 1 , wherein the first amount is a thickness of approximately 0.0 to 8 mm. 
     
     
         12 . The process of  claim 1 , wherein the second amount or third amount is a thickness of approximately 0.3 to 3.2 mm. 
     
     
         13 . The process of  claim 1 , wherein the second amount is a thickness of approximately 0.5 to 1.0 mm. 
     
     
         14 . The process of  claim 1 , wherein the third amount is a thickness of approximately 0.3 to 1.0 mm. 
     
     
         15 . The process of  claim 1 , wherein the second amount comprises at least one from the group consisting of: TiN, Al 2 O 3 , AlN, TiC, Ti 2 AlN, TiCN, ZrN, ZrO 2 , and HfO 2 . 
     
     
         16 . The process of  claim 15 , wherein in the second amount the second concentration of cBN is greater than a concentration of at least one from the group consisting of: TiN, Al 2 O 3 , AlN, Ti 2 AlN, TiC, TiCN, ZrN, ZrO 2 , and HfO 2 . 
     
     
         17 . The process of  claim 15 , wherein a first concentration of TiN or Al 2 O 3  in the second amount is less than a second concentration of TiN or Al 2 O 3  in the third amount. 
     
     
         18 . The process of  claim 1 , wherein the deposited second amount or third amount is in the form of a pre-compacted disk. 
     
     
         19 . The process of  claim 1 , wherein the deposited second amount or third amount is in the form of a powder. 
     
     
         20 . The process of  claim 1 , wherein the substrate includes metal carbo nitrides of the form Me (C,N). 
     
     
         21 . A polycrystalline cubic boron nitride (PcBN) cutting tool, comprising:
 in a content to which high pressure and high temperature (HPHT) is applied:
 a first amount of a substrate; 
 a second amount of at least a cubic boron nitride (cBN); and 
 a third amount of a mixture of cBN and ceramic. 
   
     
     
         22 . The PcBN of  claim 21 , wherein the substrate comprises at least one of a metal and silicon. 
     
     
         23 . The PcBN of  claim 21 , wherein the content is contained in a refractory capsule formed from a foil sheet or wrap of tantalum (Ta), molybdenum (Mo), or a grade IV-VI transition metal. 
     
     
         24 . The PcBN of  claim 21 , wherein the substrate includes carbide. 
     
     
         25 . The PcBN of  claim 21 , wherein the ceramic includes at least one from a group consisting of: TiN, Al 2 O 3 , AlN, TiC, TiCN, ZrN, ZrO 2 , and HfO 2 . 
     
     
         26 . The PcBN of  claim 21 , wherein a first concentration of cBN in the third amount is lower than a second concentration of cBN in the second amount, 
     
     
         27 . The PcBN of  claim 24 , wherein upon applying the HPHT, carbide of the substrate first diffuses across the second amount of at least the cBN, and then diffuses across the third amount of the mixture of the cBN and ceramic. 
     
     
         28 . The PcBN of  claim 21 , wherein the first amount is a thickness of approximately 0.0 to 8 mm. 
     
     
         29 . The PcBN of  claim 21 , wherein the second amount or third amount is a thickness of approximately 0.3 to 3.2 mm. 
     
     
         30 . The PcBN of  claim 21 , wherein the second amount is a thickness of approximately 0.5 to 1.0 mm. 
     
     
         31 . The PcBN of  claim 21 , wherein the third amount is a thickness of approximately 0.3 to 1.0 mm. 
     
     
         32 . The PcBN of  claim 21 , wherein the second amount comprises at least one from the group consisting of: TiN, Al 2 O 3 , AlN, TiC, Ti 2 AlN, TiCN, ZrN, ZrO 2 , and HfO 2 . 
     
     
         33 . The PcBN of  claim 25 , wherein in the second amount the second concentration of cBN is greater than a concentration of at least one from the group consisting of: TiN, Al 2 O 3 , AlN, Ti 2 AlN, TiC, TiCN, ZrN, ZrO 2 , and HfO 2 . 
     
     
         34 . The PcBN of  claim 25 , wherein a first concentration of TiN or Al 2 O 3  in the second amount is less than a second concentration of TiN or Al 2 O 3  in the third amount. 
     
     
         35 . The PcBN of  claim 21 , wherein the second amount or third amount of the content is in the form of a pre-compacted disk. 
     
     
         36 . The PcBN of  claim 21 , wherein the second amount or third amount of the content is in the form of a powder. 
     
     
         37 . The PcBN of  claim 21 , wherein the substrate includes metal carbo nitrides of the form Me (C,N). 
     
     
         38 . A process of fabricating a polycrystalline cubic boron nitride (PcBN) cutting tool, comprising:
 depositing:
 a first amount of a mixture of a cubic boron nitride (cBN) and ceramic; 
 a second amount of at least cBN; 
 a third amount of a substrate; and 
   applying a high pressure and high temperature (HPHT).