Cutting tool made of hard metal and provided with a layer of diamond and process for producing thereof

摘要

Diamond-coated hard metal cutting tool consists of a diamond layer on a substrate, and a carbon layer. The diamond layer is polycrystalline and the diamond crystals are statically orientated. The carbon layer has an amorphous structure and contains less than 70% covalent sp3 bonds of carbon atoms. An Independent claim is also included for a diamond-coated hard metal cutting tool comprising coating a hard metal base body with a crystalline diamond layer in a CVD process at above 800 degrees C, carrying out PVD-Re sputtering to change the sp3 diamond coating to an sp2 double bonds, and applying a carbon coating in a PVD process at less than 500 degrees C so that the carbon layer is formed as an amorphous structure by adding a reactive gas.