Cubic Boron Nitride Particle Population with Highly-Etched Particle Surface and High Toughness Index

Abstract

A cubic boron nitride particle population having highly-etched surfaces and a high toughness index is produced by blending a reactive metal powder with a plurality of cubic boron nitride particles to form a blended mixture. The blended mixture is compressed to form a compressed mixture. The compressed mixture is subjected to a temperature and a pressure, where the temperature is controlled to cause etching of the plurality of cubic boron nitride particles by reaction of cubic boron nitride with the reactive metal powder, thereby forming a plurality of etched cubic boron nitride particles. Also, the temperature and pressure are controlled to cause boron nitride to remain in a cubic boron nitride phase. Afterwards, the plurality of etched cubic boron nitride particles is recovered from the compressed mixture to form the particle population. Preferably, the particle population contains no hexagonal boron nitride.

1 . A plurality of etched cubic boron nitride particles, wherein each of the cubic boron nitride particles includes a plurality of pits, a plurality of grooves and a toughness index of a particle population is about 10 to about 20 points lower than a non-etched, non-rough cubic boron nitride particle population with the same chemical composition, crystal structure and shape. 
     
     
         2 . The particle population of  claim 1 , wherein each of the plurality of pits has a width between about 500 nanometers and about 1.5 microns and a depth of about 100 nanometers to 1 about micron. 
     
     
         3 . The particle population of  claim 1 , wherein each of the plurality of the grooves has a length between about 5 microns and about 30 microns and a depth of about 100 nanometers to 1 about micron and a width of about 500 nanometers. 
     
     
         4 . The particle population of  claim 1 , wherein each of the plurality of etched cubic boron nitride particles is a monocrystalline cubic boron nitride particle. 
     
     
         5 . The particle population of  claim 1  wherein each of the plurality of etched cubic boron nitride particles is a polycrystalline cubic boron nitride particle. 
     
     
         6 . The particle population of  claim 1 , wherein a size of each particle is between 10 microns and 1000 microns. 
     
     
         7 . The particle population of  claim 1 , wherein a particle surface covered by pits and grooves is between about 20% and 60%. 
     
     
         8 . The particle population of  claim 1 , wherein the particles are coated with a layer of glass. 
     
     
         9 . The particle population of  claim 8 , wherein a glass weight percent is less than 10% of a weight of the particle. 
     
     
         10 . The particle population of  claim 1 , wherein the particles are covered by an oxide. 
     
     
         11 . The particle population of  claim 1 , wherein the particles are covered by a metal. 
     
     
         12 . The particle population of  claim 11 , wherein the metal is nickel. 
     
     
         13 . The particle population of  claim 11 , wherein the metal is titanium. 
     
     
         14 . A method for producing a particle population, the method comprising:
 blending a reactive metal powder with a plurality of cubic boron nitride particles to form a blended mixture:   compressing the blended mixture to form a compressed mixture;   subjecting the compressed mixture to a temperature and a pressure, wherein the temperature is controlled to cause etching of the plurality of cubic boron nitride particles by reaction of cubic boron nitride with the reactive metal powder, thereby forming a plurality of etched cubic boron nitride particles, and the temperature and pressure are controlled to cause boron nitride to remain in a cubic boron nitride phase: and recovering the plurality of etched cubic boron nitride particles from the compressed mixture to form the particle population.   
     
     
         15 . The method of  claim 14 , wherein the pressure is about gigapascals or greater. 
     
     
         16 . The method of  claim 14 , wherein the temperature is about 1300° C. or greater. 
     
     
         17 . The method of  claim 14 , wherein the particle population contains no hexagonal boron nitride. 
     
     
         18 . The method of  claim 14 , wherein a toughness index of the particle population is about 10 to about 20 points lower than a non-etched, non-rough cubic boron nitride particle population with the same chemical composition, crystal structure and shape. 
     
     
         19 . The method of  claim 14 , wherein each of the plurality of cubic boron nitride particles is a monocrystalline cubic boron nitride particle. 
     
     
         20 . The method of  claim 14 , wherein each of the plurality of cubic boron nitride particles is a polycrystalline cubic boron nitride particle. 
     
     
         21 . The method of  claim 14 , wherein the reactive metal powder is chosen from lithium, beryllium, calcium, strontium, magnesium, titanium, zirconium, aluminum, gallium, indium, tungsten, hafnium, chromium, cobalt, nickel, vanadium, tantalum, niobium, and iron. 
     
     
         22 . The method of  claim 14 , wherein a particle size is between 10 microns and 1000 microns. 
     
     
         23 . The method of  claim 14 , wherein each of the plurality of etched cubic boron nitride particles includes a plurality of pits and a plurality of grooves, and each of the plurality of pits has a width between about 500 nanometers and about 1.5 microns, and a depth between about 100 nanometers and about 1 micron, and each of the plurality of grooves has a width of about 500 nanometers, and a length of about 5 microns and about 30 microns, and a depth of about 100 nanometers to about 1 micron.