Method for treating a superhard composite material intended for being used in the production of cutting tools

Abstract

The invention relates to a method of processing a superhard composite material ( 21 ) comprising a polycrystalline microstructure and a binder, said method comprising the following steps: contacting ( 200 ) a surface of said superhard composite material ( 21 ) with an absorbent material ( 30 ), and applying ( 300 ) an electric current to the superhard composite material ( 21 ), causing the binder to move from the superhard composite material ( 21 ) to the absorbent material ( 30 ) so as to create a continuous gradient ( 221 ) of binder content within the superhard composite material ( 21 ).

1 . A method of treating a superhard composite material ( 21 ) comprising a polycrystalline microstructure and a binder, said method comprising the following steps:
 contacting ( 200 ) a surface of said superhard composite material ( 21 ) with an absorbent material ( 30 ), and   applying ( 300 ) an electric current to the superhard composite material ( 21 ), causing the binder to move from the superhard composite material ( 21 ) to the absorbent material ( 30 ) so as to create a continuous gradient ( 221 ) of binder content within the superhard composite material ( 21 ).   
     
     
         2 . The method according to  claim 1  characterized in that the polycrystalline microstructure includes crystals selected from the crystals of: tungsten carbide, diamond, silicon carbide, silicon nitride, and boron nitride. 
     
     
         3 . The method according to one of  claims 1  or  2  characterized in that the polycrystalline microstructure consists essentially of tungsten carbide crystals. 
     
     
         4 . The method according to any one of  claims 1 to 3  characterized in that the binder includes at least one element selected from the following elements: iron, ruthenium, osmium, hassium, cobalt, rhodium, iridium, meitnerium, nickel, palladium, platinum, darmstadtium, molybdenum, and titanium. 
     
     
         5 . The method according to any one of  claims 1 to 4  characterized in that the binder includes cobalt. 
     
     
         6 . The method according to any one of  claims 1 to 5  characterized in that the absorbent material ( 30 ) is capable of interacting with the binder so as to form binary, ternary, or quaternary compounds. 
     
     
         7 . The method according to any one of  claims 1 to 6  characterized in that the absorbent material ( 30 ) is provided on a surface adjacent to an area to be binder-depleted. 
     
     
         8 . The method according to any one of  claims 1 to 7  characterized in that the electric current applied to the superhard composite material (21) has an electric current density between 0.1 and 50 A/mm 2 . 
     
     
         9 . The method according to any one of  claims 1 to 8  characterized in that the electric current is applied over a period of at least five minutes. 
     
     
         10 . The method according to any one of  claims 1 to 9  characterized in that the electric current is applied to the superhard composite material ( 21 ) via electrodes positioned, on the one hand, on a surface adjacent to an area to be binder-depleted, and, on the other hand, to a surface opposite to the area to be binder-depleted. 
     
     
         11 . The method according to any one of  claims 1 to 10 , characterized in that it is carried out at a temperature lower than the melting temperature of the binder. 
     
     
         12 . A superhard composite material including a binder-depleted area ( 22 ) characterized in that the binder-depleted zone ( 22 ) has a continuous gradient ( 221 ) of binder content extending over a depth greater than or equal to 500 µm. 
     
     
         13 . A cutting, machining, or drilling tool comprising the superhard composite material according to  claim 12 .