Graded drilling cutter

Abstract

In an embodiment, an abrasive compact includes ultra-hard particles which are sintered, bonded, or otherwise consolidated into a solid body. The compact also includes various physical characteristics having a continuous gradient, a multiaxial gradient, or multiple independent gradients.

1 . An abrasive compact comprising:
 a plurality of superabrasive particles consolidated into a solid mass, the particles having a characteristic gradient that is continuous, monotonic and uniaxial.   
     
     
         2 . The abrasive compact of  claim 1  wherein the characteristic gradient comprises a particle size gradient. 
     
     
         3 . The compact of  claim 2  in which a maximum rate of change of particle size is less than 1 micron of particle size per 1 micron of translation. 
     
     
         4 . The abrasive compact of  claim 1 , wherein the characteristic gradient comprises a pore size gradient. 
     
     
         5 . The compact of  claim 4  in which a maximum rate of change of pore size is less than 1 micron of diameter per 1 micron of translation. 
     
     
         6 . The abrasive compact of  claim 1 , wherein the characteristic gradient comprises a particle shape gradient. 
     
     
         7 . The compact of  claim 6  in which a maximum rate of change of particle aspect ratio is less than 0.1 per 1 micron of translation. 
     
     
         8 . The abrasive compact of  claim 1 , wherein the characteristic gradient comprises a concentration of the superabrasive particles. 
     
     
         9 . An abrasive compact comprising:
 a plurality of superabrasive particles consolidated into a solid mass, the mass having a first continuous gradient along a first axis of the mass and a second continuous gradient along a second axis of the mass.   
     
     
         10 . The compact of  claim 9 , wherein each of the gradients comprises a particle size gradient. 
     
     
         11 . The compact of  claim 9 , wherein the first continuous gradient comprises a particle size gradient and the second continuous gradient comprises one of a pore size gradient, a particle shape gradient, or a superabrasive particle concentration gradient. 
     
     
         12 . The compact of  claim 11 , wherein the first continuous gradient is monotonic and uniaxial. 
     
     
         13 . The compact of  claim 11 , wherein the first continuous gradient is oscillating. 
     
     
         14 . A method of creating an abrasive compact, comprising:
 combining ultra-hard particles with a fluid to create a mixed slurry;   allowing the mixed slurry to separate and form a graded layer;   removing remaining liquid from the graded layer;   selecting a portion of the graded layer;   placing a substrate against the selected portion of the graded layer to create an initial assembly;   processing the initial assembly to produce a sintered abrasive compact supported on the substrate to form a recovered assembly; and   finishing the supported sintered compact into an abrasive tool.   
     
     
         15 . The method of  claim 14 :
 wherein the allowing comprises allowing the mixed slurry to settle in a non-planar fixture; and   wherein the placing comprises placing an interface surface of the substrate so that the interface surface matches a surface of the graded layer.   
     
     
         16 . The method of  claim 14 , wherein the placing comprises orienting the graded layer and the substrate so that a surface of the substrate having more coarse particles is near the substrate.