Polycrystalline diamond compact cutters having protective barrier coatings

A polycrystalline diamond compact cutter comprising:

• a cemented carbide body as a supporting substrate;
• an unleached or leached polycrystalline diamond table as a cutting element which is disposed on the supporting substrate;
• and
• a coating covering at least a portion of the exterior surfaces of the polycrystalline diamond table, wherein the coating comprises an oxidation-resistant layer of a compound selected from carbides, nitrides, borides, oxides, or their complex compounds, and wherein the coating has a metallurgical bonding with the polycrystalline diamond table, which is characterized by formation of a compound containing carbon at their interface.

A method of coating a polycrystalline diamond compact cutter with a protective barrier coating, comprising physical vapor deposition including thermal evaporation, sputtering, and ion plating;

• wherein the polycrystalline diamond compact cutter comprising:
• a cemented carbide body as a supporting substrate;
• a leached polycrystalline diamond table as a cutting element which is disposed on the supporting substrate;
• and
• the protective barrier coating covering at least a portion of the exterior surfaces of the polycrystalline diamond table.