Research on the cutting performance of carbon nitride cutting tools

A new kind of superhard material C 3N 4 has been developed in recent years. C 3N 4 film is deposited on the surface of cutting tools by the dc active magnetron-sputtering method. It has ultrahigh hardness approaching that of diamond. A high speed steel (HSS) twist drill coated with C 3N 4 film is applied to drilling hole process in steel workpiece in cutting tests, the tool life being found to increase greatly. When the C 3N 4 film is coated on cemented carbide inserts, whilst the cutting performance is improved, it is not good enough. When a C 3N 4 coated cemented carbide tool is used in machining particle reinforced composite material (PRCM), the cutting performance is almost as poor as when machining with an uncoated tool. The data of the mechanical properties and cutting tests of about this kind of new coated cutting tool are given in this paper, showing that C 3N 4 has a promising future.