Ultrasharp diamond edges and points and method of making

A method of making ultrasharp diamond edges and points which comprises preparing ultrafine diamond powder having a particle size of 10 to 100 angstroms, placing a measured quantity of said powder in a diamond mold having therein a mold cavity defining the ultrasharp edge or point to be produced, placing said mold with said diamond powder therein in a fluid-tight envelope, evacuating the space within said envelope to achieve an ultrahigh vacuum of 10.sup.-8 to 10.sup.-9 Torr to thoroughly degas said ultrafine diamond powder and mold inside said envelope, and concurrently applying to said ultrafine diamond powder in said mold a pressure of the order of 50 kb to 90 kb and a temperature of 2000.degree. to 2500.degree. K while maintaining said mold and diamond powder in said ultrahigh vacuum to avoid oxidation of said ultrafine diamond powder, to thereby bond the particles of said ultrafine diamond powder together to form an ultrahard sintered body having an ultrasharp edge or point as defined by said mold.

A method of making ultrasharp diamond edges and points which comprises preparing ultrafine diamond powder having a particle size of 10 to 100 angstroms, classifying said ultrafine diamond powder by differential and densitygradient ultracentrifugation of an oil or glycerol suspension of said powder at 60,000 to 100,000 .times. g to separate out any diamond particles having a particle size larger than 100 angstroms, placing a measured quantity of said powder of which all particles have a particle size less than 100 angstroms in a diamond mold having therein a mold cavity defining an edge or point having a radius of 10 to 100 angstroms, placing said mold with said diamond powder therein in a fluid-tight envelope, evacuating the space within said envelope to achieve an ultrahigh vacuum to thoroughly degas said ultrafine diamond powder and the mold inside said envelope, and concurrently applying to said ultrafine diamond powder in said mold a pressure of the order of 50 kb to 90 kb and a temperature of 2000.degree. to 2500.degree. K while maintaining said mold and diamond powder in said ultrahigh vacuum to avoid oxidation of said ultrafine diamond powder to thereby bond the particles of said ultrafine diamond powder together to form an ultrahard sintered body having an ultrasharp edge or point with a radius of 10 to 100 angstroms as defined by said mold.

A method of making ultrafine diamond edges and points which comprises preparing ultrafine diamond powder in the form of platelets having a thickness of the order of 6 angstroms and a length of 10 to 100 angstroms, placing a measured quantity of said powder in a diamond mold having therein a mold cavity defining the ultrasharp edge or point to be produced, placing said mold with said diamond powder therein in a fluid-tight envelope, evacuating the space within said envelope to achieve an ultrahigh vacuum to thoroughly degas said ultrafine diamond powder and the mold inside said envelope, and concurrently applying to said ultrafine diamond powder in said mold a pressure of the order of 50 kb to 90 kb and a temperature of 2000.degree. to 2500.degree. K while maintaining said mold and diamond powder in an ultrahigh vacuum or atmosphere of noble gas to avoid oxidation of said diamond powder, to thereby bond said particles of said diamond powder together to form an ultrahard sintered body having an ultrasharp edge or point as defined by said mold.

A method of making ultrasharp diamond edges and points which comprises preparing ultrafine diamond powder having a particle size of 10 to 100 angstroms, the particles of said diamond particles having 1-1-1 faces, placing a measured quantity of said powder in a diamond mold having therein a mold cavity defining the ultrasharp edge or point to be produced, orienting the particles of ultrafine diamond powder in said mold to present 1-1-1 faces of said particles at the edge or point of the article being made, placing said mold with said oriented particles of diamond powder therein in a fluid-tight envelope, evacuating the space within said envelope to achieve an ultrahigh vacuum to thoroughly degas said ultrafine diamond powder and the mold inside said envelope, and concurrently applying to said ultrafine diamond powder in said mold a pressure of the order of 50 kb to 90 kb and a temperature of 2000.degree. to 2500.degree. K while maintaining said mold and diamond powder in an ultrahigh vacuum or atmosphere of noble gas to avoid oxidation of said diamond powder, to thereby bond said particles of said diamond together to form an ultrahard sinterted body having an ultrasharp edge or point formed by said 1-1-1 faces of said diamond particles.

A polycrystalline diamond cutting implement having an ultrasharp edge or point, said implement comprising a multiplicity of diamond particles molecularly bonded together with the cohesion of natural diamond, all of said diamond particles being of a size less than 100 angstroms and being uniformly oriented to present like faces to said edge or point to define a continuous uniform edge or point having a radius of from 10 to 100 angstroms.