Coated cutting tools having a platinum group metal concentration gradient and related processes

Abstract

The present disclosure is directed to cutting tools. The disclosed cutting tools may have a wear resistant coating on a substrate. The substrate may have hard particles cemented in a binder phase. The binder may have a near-surface concentration gradient of at least one platinum group element and/or rhenium. Processes for producing cutting tools are also disclosed.

What is claimed is: 
     
         1 . A process for producing a cutting tool comprising:
 etching at least a portion of a surface of a cemented carbide substrate comprising:
 hard particles comprising tungsten carbide; and 
 a binder comprising cobalt; 
   depositing ruthenium onto at least a portion of the surface of the cemented carbide substrate;   heating the substrate at a temperature and for a time sufficient to cause the ruthenium to diffuse into the binder and form a near-surface ruthenium concentration gradient in the binder; and   depositing a wear resistant coating onto the substrate surface after heating the substrate and forming the near-surface ruthenium concentration gradient in the binder;   wherein the near-surface ruthenium concentration gradient comprises from 10 weight percent to 100 weight percent ruthenium, on a total binder weight basis, at the substrate surface, and the concentration of ruthenium decreases with depth below the substrate surface to zero or background levels of ruthenium in a bulk region of the substrate.   
     
     
         2 . The process of  claim 1 , wherein the near-surface ruthenium concentration gradient comprises from 10 weight percent to 100 weight percent ruthenium, on a total binder weight basis, at the substrate surface, and the concentration of ruthenium decreases logarithmically with depth below the substrate surface to zero or background levels of platinum group metal in a bulk region of the substrate. 
     
     
         3 . The process of  claim 1 , further comprising, after the heating of the substrate and before the depositing of the wear resistant coating onto the substrate surface, treating at least a portion of the substrate surface with a pre-coating treatment. 
     
     
         4 . The process of  claim 3 , wherein the pre-coating treatment comprises electropolishing, shot peening, microblasting, wet blasting, dry blasting, grinding, brushing, jet abrading, compressed air blasting, or combinations of any thereof. 
     
     
         5 . The process of  claim 3 , wherein the pre-coating treatment comprises microblasting, wet blasting, dry blasting, or combinations of any thereof. 
     
     
         6 . The process of  claim 1 , wherein the wear resistant coating is deposited using physical vapor deposition. 
     
     
         7 . The process of  claim 1 , wherein the wear resistant coating is deposited using chemical vapor deposition. 
     
     
         8 . The process of  claim 1 , wherein the wear resistant coating comprises at least one of a metal carbide, a metal nitride, a metal carbonitride, a metal boride, a metal silicide, or a metal oxide. 
     
     
         9 . The process of  claim 8 , wherein the metal comprising the wear resistant coating comprises titanium, chromium, vanadium, zirconium, hafnium, tantalum, molybdenum, niobium, tungsten, aluminum, boron, silicon, or combinations of any thereof. 
     
     
         10 . A process for producing a cutting tool comprising:
 depositing at least one platinum group metal onto at least a portion of a surface of a substrate comprising hard particles and a binder;   heating the substrate at a temperature and for a time sufficient to cause at least one platinum group metal to diffuse into the binder and form a near-surface platinum group metal concentration gradient in the binder; and   depositing a wear resistant coating onto the substrate surface after heating the substrate and forming the near-surface platinum group metal concentration gradient in the binder.   
     
     
         11 . The process of  claim 10 , wherein the platinum group metal comprises rhenium, ruthenium, osmium, rhodium, iridium, palladium, platinum, or combinations of any thereof. 
     
     
         12 . The process of  claim 10 , wherein the hard particles comprise at least one metal carbide, metal nitride, metal carbonitride, metal boride, metal silicide, metal oxide, or combination of any thereof. 
     
     
         13 . The process of  claim 12 , wherein the metal comprising the hard particles comprises titanium, chromium, vanadium, zirconium, hafnium, tantalum, molybdenum, niobium, tungsten, or combinations of any thereof. 
     
     
         14 . The process of  claim 10 , wherein the binder comprises cobalt, nickel, iron, alloys of any thereof, or combinations of any thereof. 
     
     
         15 . The process of  claim 10 , wherein the near-surface platinum group metal concentration gradient comprises from 10 weight percent to 100 weight percent platinum group metal, on a total binder weight basis, at the substrate surface, and the platinum group metal concentration decreases with depth below the substrate surface to zero or background levels of platinum group metal in a bulk region of the substrate. 
     
     
         16 . The process of  claim 10 , wherein the near-surface platinum group metal concentration gradient comprises from 10 weight percent to 100 weight percent platinum group metal, on a total binder weight basis, at the substrate surface, and the platinum group metal concentration decreases logarithmically with depth below the substrate surface to zero or background levels of platinum group metal in a bulk region of the substrate. 
     
     
         17 . The process of  claim 10 , further comprising removing a portion of the binder from at least a portion of the substrate surface before depositing at least one platinum group metal onto at least a portion of the surface of the substrate. 
     
     
         18 . The process of  claim 17 , comprising etching the substrate surface to remove a portion of the binder from at least a portion of the substrate surface before depositing at least one platinum group metal onto at least a portion of the surface of the substrate. 
     
     
         19 . The process of  claim 10 , wherein the wear resistant coating is deposited using physical vapor deposition. 
     
     
         20 . The process of  claim 10 , wherein the wear resistant coating is deposited using chemical vapor deposition. 
     
     
         21 . The process of  claim 10 , wherein the wear resistant coating comprises at least one of a metal carbide, a metal nitride, a metal carbonitride, a metal boride, a metal silicide, or a metal oxide. 
     
     
         22 . The process of  claim 21 , wherein the metal comprising the wear resistant coating comprises titanium, chromium, vanadium, zirconium, hafnium, tantalum, molybdenum, niobium, tungsten, aluminum, boron, silicon, or combinations of any thereof. 
     
     
         23 . The process of  claim 18 , further comprising, after the heating of the substrate and before the depositing of the wear resistant coating onto the substrate surface, treating at least a portion of the substrate surface with a pre-coating treatment. 
     
     
         24 . The process of  claim 23 , wherein the pre-coating treatment comprises electropolishing, shot peening, microblasting, wet blasting, dry blasting, grinding, brushing, jet abrading, compressed air blasting, or combinations of any thereof. 
     
     
         25 . A cutting tool comprising:
 a cemented carbide substrate comprising tungsten carbide particles and a binder comprising cobalt, the binder further comprising a near-surface ruthenium concentration gradient of 10 weight percent to 100 weight percent ruthenium on a total binder weight basis at the substrate surface and decreasing with depth below the substrate surface to zero or background levels of ruthenium in a bulk region of the substrate; and   at least one wear resistant coating on at least a portion of the substrate, the wear resistant coating comprising at least one of titanium nitride, titanium carbide, titanium carbonitride, titanium aluminum nitride, or aluminum oxide.