Multilayer coating process protecting the substrate of thermally stable polycrystalline diamond cutter

Abstract

A method for making a polycrystalline diamond compact including the step of providing a polycrystalline diamond compact. The compact has a substrate of a hard metal composition of material and a volume of diamond material disposed on the substrate. The diamond material includes a mixture of diamond particles and a binder-catalyst. At least one pre-coating layer of organic material impermeable to a given acid or mixture of given acids is applied to at least an exterior surface of the substrate. At least one layer of primer material that is impermeable to a given acid or mixture of given acids is applied on the at least one pre-coating layer. A layer of top coating material that is impermeable to the given acid or mixture of given acids is applied to the at least one primer layer. When the given acid or mixture of given acids is applied to the compact to leach the binder-catalyst from the diamond material the at least one pre-coating layer, at least one primer layer and layer of top coating material protect the coated portions of the compact.

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         11 . A method for making a polycrystalline diamond compact comprising the steps of:
 providing a polycrystalline diamond compact, the compact having a substrate of a hard metal composition of material and a volume of diamond material disposed on the substrate;   applying at least one pre-coating layer of organic material impermeable to a given acid or mixture of given acids to at least an exterior surface of the substrate;   applying at least one layer of primer material that is impermeable to a given acid or mixture of given acids on the at least one pre-coating layer; and   applying a layer of top coating material that is impermeable to the given acid or mixture of given acids to the at least one primer layer.   
     
     
         12 . The method of  claim 11 , wherein the binder-catalyst is selected from the group of cobalt, silicon, boron, zirconium, aluminum, ruthenium, chromium, manganese, molybdenum, platinum, palladium and mixtures of such. 
     
     
         13 . The method of  claim 11 , wherein the hard composition of material is cemented carbide selected from the group of tungsten, silicon, chromium, vanadium, tantalum, niobium, titanium, nickel, cobalt, iron and combinations thereof. 
     
     
         14 . The method of  claim 11 , wherein the at least one primer layer is applied in a thickness of about 1 μm to about 100 μm. 
     
     
         15 . The method of  claim 11 , wherein the at least one primer layer is a coating of polymeric material selected from the group of polytetrafluoroethylene (PTFE) or perfluoroalkoxy (PFA) based polymers. 
     
     
         16 . The method of  claim 11 , wherein the step of applying at least one primer layer comprises coating an entire surface of the substrate of the compact. 
     
     
         17 . The method of  claim 11 , wherein the step of applying at least one primer layer comprises coating an entire surface of substrate of the compact with a plurality of primer layers of material. 
     
     
         18 . The method of  claim 11 , wherein the step of applying at least one primer layer comprises coating an entire surface of the substrate and a portion of the volume of diamond material of the compact. 
     
     
         19 . The method of  claim 18 , wherein the step of applying at least one primer layer comprises coating the entire surface of the substrate and a portion of the volume of diamond material of the compact with a plurality of layers of primer material. 
     
     
         20 . The method of  claim 11 , wherein the step of applying at least one layer of primer material comprises coating the entire surface of the substrate and the volume of diamond material of the compact and further comprising the step of selectively removing a part of the coating from the volume of diamond material. 
     
     
         21 . The method of  claim 11 , wherein the layer of top coating is applied in a thickness of about 1 μm to about 100 μm. 
     
     
         22 . The method of  claim 11 , wherein the layer of top coating is a coating of polymeric material selected from the group of polytetrafluoroethylene (PTFE) or perfluoroalkoxy (PFA) based polymers. 
     
     
         23 . The method of  claim 11 , wherein the step of applying the layer of top coating comprises coating an entire surface of the substrate and a portion of the volume of diamond material of the compact. 
     
     
         24 . The method of  claim 11 , wherein the step of applying the layer of top coating comprises coating an entire surface of the substrate and volume of diamond material of the compact and further comprising the step of selectively removing a part of the top coating from the volume of diamond material. 
     
     
         25 . The method of  claim 11 , further comprising the step of applying the given acid or mixture of given acids to the compact to leach the binder-catalyst from only the diamond material. 
     
     
         26 . The method of  claim 11 , wherein the at least one protective pre-coating layer is a coating of organic material selected from the group of photoresist polymers. 
     
     
         27 . The method of  claim 11 , wherein the at least one protective pre-coating layer is applied in a thickness of about 1 μm to about 100 μm. 
     
     
         28 . The method of  claim 11 , wherein a total thickness of the pre-coat layer, the at least one primer layer and the top coat layer applied is at a minimum of about 200 μm.