Superabrasive particle synthesis with growth control

Abstract

An improved method for synthesizing superabrasive particles provides high quality industrial superabrasive particles with high yield and a narrow size distribution. The synthesis method can include forming a growth precursor of a substantially homogeneous mixture of raw material and catalyst material or layers of raw material and metal catalyst. The growth precursor can have a layer of adhesive over at least a portion thereof. A plurality of crystalline seeds can be placed in a predetermined pattern on the layer of adhesive. The growth precursor can be maintained at a temperature and pressure at which the superabrasive crystal is thermodynamically stable for a time sufficient for a desired degree of growth. Advantageously, the patterned placement of crystalline seeds and disclosed processes allow for production of various morphologies of synthetic diamonds, including octahedral and cubic diamonds, and improved growth conditions generally. As a result, the grown superabrasive particles typically have a high yield of high quality particles and a narrow distribution of particle sizes.

1 . A method for synthesizing superabrasive particles, comprising the steps of: 
 providing a growth precursor including a raw material and a catalyst material, and having crystalline seeds arranged at least partially therein;    selecting a temperature profile that promotes superabrasive particle growth in either octahedral or cubic shape; and    growing the superabrasive particles under pressure and the selected temperature profile in order to grow superabrasive particles having a preselected morphology.    
   
   
       2 . The method of  claim 1 , wherein the temperature profile includes elevating the temperature to a set-point and maintaining the temperature at the set-point for the duration of processing.  
   
   
       3 . The method of  claim 1 , wherein the temperature profile includes more than one processing temperature.  
   
   
       4 . The method of  claim 3 , wherein the temperature profile includes step-wise adjustments to temperature.  
   
   
       5 . The method of  claim 3 , wherein the temperature profile includes continuous adjustments to temperature.  
   
   
       6 . The method of  claim 1 , wherein the temperature profile is selected to promote a substantially even relative growth rate perpendicular to (100) and (111) faces.  
   
   
       7 . The method of  claim 1 , wherein the temperature profile is selected to promote growth perpendicular to an (111) face.  
   
   
       8 . The method of  claim 7 , wherein the temperature profile includes a set-point of about 1250° C. to about 1310° C.  
   
   
       9 . The method of  claim 7 , wherein the preselected morphology is dominantly cubic or cubo-octahedral.  
   
   
       10 . The method of  claim 7 , wherein greater than about 70% of the superabrasive particles are cubic.  
   
   
       11 . The method of  claim 1 , wherein the temperature profile is selected to promote growth perpendicular to an (100) face.  
   
   
       12 . The method of  claim 11 , wherein the temperature profile includes a set-point of about 1305° C. to about 1320° C.  
   
   
       13 . The method of  claim 11 , wherein the preselected morphology is dominantly octahedral.  
   
   
       14 . The method of  claim 11 , wherein greater than about 70% of the superabrasive particles are octahedral.  
   
   
       15 . The method of  claim 1 , wherein the temperature profile is adjusted based on the crystalline seed morphology.  
   
   
       16 . The method of  claim 1 , wherein the superabrasive particles are diamond and the raw material is a carbon source.  
   
   
       17 . The method of  claim 1 , wherein the pressure is constant.  
   
   
       18 . A method for controlling superabrasive particle shape during growth from crystalline seeds under high pressure and temperature conditions, comprising utilizing a temperature selected to direct growth of superabrasive particles in either an octahedral or a cubic morphology.  
   
   
       19 . The method of  claim 18 , wherein the morphology is cubic and the temperature selected to direct growth of superabrasive particles is about 1250° C. to about 1310° C.  
   
   
       20 . The method of  claim 18 , wherein the morphology is octahedral and the temperature selected to direct growth of superabrasive particles is about 1305° C. to about 1320° C.  
   
   
       21 . The method of  claim 18 , wherein the superabrasive particles are diamond.