Abrasive and wear resistant material

Abstract

An abrasive and wear resistant material comprises a mass of carbide particles, a mass of cubic boron nitride particles, and a bonding metal or alloy, bonded into a coherent, sintered form. The cubic boron nitride particle content of the material is from 10% to 18% inclusive by weight, the particle size of the cubic boron nitride is less than 20 micron or less, and the material is substantially free of hexagonal boron nitride. The abrasive material is of particular use in tool components or inserts for application in the abrading of wood and other lignocellulosic materials.

1 . An abrasive and wear resistant material comprising a mass of carbide particles, a mass of cubic boron nitride particles, and a bonding metal or alloy bonded into a coherent, sintered form, wherein: 
 the cubic boron nitride particle content of the material is from 10% to 18% inclusive by weight;    the particle size of the cubic boron nitride is 20 micron or less; and    the material is substantially free of hexagonal boron nitride.    
     
     
         2 . A material according to  claim 1  wherein the carbide particles are particles selected from the group consisting of tungsten carbide, tantalum carbide, titanium carbide, niobium carbide and mixtures thereof.  
     
     
         3 . A material according to  claim 1  or  claim 2  wherein the bonding metal or alloy is selected from the group consisting of cobalt, iron, nickel and alloys containing one or more of these metals.  
     
     
         4 . A material according to any one of  claims 1  to  3  wherein the bonding metal or alloy content of the material is from 3% to 15% inclusive by weight of the material.  
     
     
         5 . A method of producing an abrasive and wear resistant material including the steps of providing a mixture of a mass of discrete carbide particles and a mass of cubic boron nitride particles, the cubic boron nitride particles being present in the mixture in an amount such that the cubic boron nitride content of the material is from 10% to 18% inclusive by weight, and wherein the cubic boron nitride particles have a particle size of 20 micron or less; and subjecting the mixture to elevated temperature and pressure conditions at which the cubic boron nitride is crystallographically stable and at which substantially no hexagonal boron nitride is formed, in the presence of a bonding metal or alloy capable of bonding the mixture into a coherent, sintered material.  
     
     
         6 . A method according to  claim 5  wherein the carbide particles are particles selected from the group consisting of tungsten carbide, tantalum carbide, titanium carbide, niobium carbide and mixtures thereof.  
     
     
         7 . A method according to  claim 5  or  claim 6  wherein the bonding metal or alloy is selected from the group consisting of cobalt, iron, nickel and alloys containing one or more of these metals.  
     
     
         8 . A method according to any one of  claims 5  to  7  wherein the bonding metal or alloy content of the material is from 3% to 15% inclusive by weight of the material.  
     
     
         9 . A method according to any one of  claims 5  to  8  wherein the bonding metal or alloy is provided in powder form or is added in the form of an organic precursor, a metal oxide or a salt precursor that is subsequently pyrolised or reduced to result in finely dispersed metal.  
     
     
         10 . A method according to any one of  claims 5  to  9  wherein the bonding metal or alloy is mixed with the mass of discrete carbide particles and the mass of cubic boron nitride particles and the mixture is then sintered.  
     
     
         11 . A method according to any one of  claims 5  to  9  wherein the bonding metal or alloy is mixed with the mass of discrete carbide particles and the mass of cubic boron nitride particles, the mixture is then cold-pressed to produce a weak coherent body, and the body is then sintered.  
     
     
         12 . A method according to any one of  claims 5  to  9  wherein the bonding metal or alloy is supplied in the form of a separate layer adjacent to the mixture of the mass of discrete carbide particles and the mass of cubic boron nitride particles and infiltrated when the mixture is subjected to the elevated temperature and pressure conditions.  
     
     
         13 . A method according to any one of  claims 5  to  12  wherein the elevated temperature and pressure conditions are at temperature of from 1200° C. to 1600° C. inclusive and a pressure of from 30 to 70 kbar inclusive.  
     
     
         14 . A method of abrading a workpiece selected from wood and other lignocellulosic materials including the steps of providing a tool having a tool component or insert comprised of an abrasive and wear resistant material comprising a mass of carbide particles, a mass of cubic boron nitride particles, and a bonding metal or alloy, bonded into a coherent, sintered form, wherein the cubic boron nitride particle content of the material is from 10% to 18% inclusive by weight, the particle size of the cubic boron nitride is less than 20 micron or less, and the material is substantially free of hexagonal boron nitride; providing the workpiece; bringing the tool component or insert into contact with the workpiece and advancing the tool component or insert into the workpiece in an abrading manner.  
     
     
         15 . A method according to  claim 14  wherein the carbide particles are particles selected from the group consisting of tungsten carbide, tantalum carbide, titanium carbide, niobium carbide and mixtures thereof.  
     
     
         16 . A method according to  claim 14  or  claim 15  wherein the bonding metal or alloy is selected from the group consisting of cobalt, iron, nickel and alloys containing one or more of these metals.  
     
     
         17 . A method according to any one of  claims 14  to  16  wherein the bonding metal or alloy content of the material is from 3% to 15% inclusive by weight of the material.