Cutter Elements for Drill Bits and Methods for Fabricating Same

Abstract

A method of fabricating a PCD cutter element including a diamond table including a plurality of coated diamond particles fabricated using an atomic layer deposition (ALD) process.

What is claimed is: 
     
         1 . A method for fabricating a PCD cutter element, comprising:
 (a) coating, by atomic layer deposition (ALD), a plurality of diamond particles by directly depositing the coating on an outer surface of each diamond particle of the plurality of diamond particles to form a plurality of coated diamond particles;   (b) removing oxides from the plurality of coated diamond particles after (a); and   (c) forming a PCD cutter element using the coated diamond particles after (b), such that the PCD cutter element has an outermost layer of uncoated diamond particles and the plurality of coated diamond particles are disposed within the outer most layer of uncoated diamond particles.   
     
     
         2 . The method of  claim 1 , wherein (c) comprises sintering the coated diamond particles and the uncoated diamond particles together to form a diamond table. 
     
     
         3 . The method of  claim 2 , wherein (c) comprises leaching the diamond table after sintering. 
     
     
         4 . The method of  claim 1 , wherein the coating deposited in (a) comprises nickel (Ni) or nickel oxide (NiO). 
     
     
         5 . The method of  claim 1 , wherein the plurality of diamond particles have an average size less than about 500 microns. 
     
     
         6 . The method of  claim 1 , wherein (b) comprises exposing the coated diamond particles to pure hydrogen at an elevated temperature. 
     
     
         7 . The method of  claim 6 , wherein the elevated temperature is between about 800° C. and about 1200° C. 
     
     
         8 . The method of  claim 7 , wherein the elevated temperature is about 1000° C. 
     
     
         9 . The method of  claim 1 , wherein the ALD is performed using a precursor comprising bis(cyclopentadienyl)cobalt(II) and hydrogen. 
     
     
         10 . The method of  claim 1 , wherein the ALD is performed using a precursor comprising bis(cyclopentadienyl)cobalt(II) and oxygen. 
     
     
         11 . The method of  claim 1 , wherein the ALD is performed using a precursor comprising bis(cyclopentadienyl)nickel(II) and hydrogen. 
     
     
         12 . The method of  claim 1 , wherein the ALD is performed using a precursor comprising bis(cyclopentadienyl)nickel(II) and oxygen. 
     
     
         13 . The method of  claim 1 , wherein the coating comprises a plurality of particles, wherein the particles of the coating have an average diameter of about 2.0 nm. 
     
     
         14 . A method of fabricating a PCD cutter element, comprising:
 (a) providing a plurality of diamond particles;   (b) directly depositing a nickel oxide coating on an outer surface of a first portion of the plurality of diamond particles by atomic layer deposition (ALD) thereby leaving a second portion of the plurality of diamond particles uncoated;   (c) removing oxides from the nickel oxide coating after (b) to convert the nickel oxide coating on the first portion of the plurality of diamond particles to a nickel coating;   (d) sintering the first portion of the plurality of diamond particles and the second portion of the plurality of diamond particles after (c) to form a diamond table, wherein the diamond table has an outermost layer formed of the second portion of the plurality of diamond particles and an inner layer disposed within the outermost layer that is formed of the first portion of the plurality of diamond particles; and   (e) mounting the diamond table to a tungsten-carbide substrate to form the PCD cutter element.   
     
     
         15 . The method of  claim 14 , further comprising (f) leaching the diamond table after (e) to remove one or more metals that infiltrate into the diamond table from the tungsten-carbide substrate. 
     
     
         16 . The method of  claim 14 , wherein the plurality of diamond particles have an average diameter from about 1 micron to about 3 microns. 
     
     
         17 . The method of  claim 14 , wherein the plurality of diamond particles have an average diameter from about 4 microns to about 8 microns. 
     
     
         18 . The method of  claim 14 , wherein (c) comprises exposing the coated diamond particles to pure hydrogen at an elevated temperature between about 800 and about 1200° C. 
     
     
         19 . The method of  claim 18 , wherein the elevated temperature is about 1000° C.