Diamond Like Structure Nano Carbonitrides Hardening of Hard Alloys Cutting Tools

摘要

The fundamental property of solid crystalline materials i.e. phenomena of first-order phase transition of grain boundaries with formation of two-dimensional liquid have been used for elaboration of the new technology. Nitriding type methods have been used to develop strategies for effective forming of coatings by synthesis of nitrides and carbonitrides on surface layers of hard metals. WC-Co and WC-TiC-Co hard metal tools have been used for experiments. Industrial tests indicated that the tools functional properties improved 2-9 times. The new tools demonstrated a high resistance to surface wear and to fragile break-down. The formed layers, interface and binder behaviour have been investigated through the experiments with use of optic and electron microscope, X-ray phase analysis and micro- hardness device measures. The layer microstructure investigation demonstrates: the hardening of thin surface layer (0.1-0.3 mm) by nanosize carbonitrides with diamond like structure and strengthening of the following layer by recristallization of W carbides grains and by formation of coherent structure in Co-binder.