Characterisation of C-B-N Diffusion Layers Developed on High-Speed Steel Substrate

Abstract

C-B-N diffusion layers on the samples of wrought and as-cast high-speed steels of AISI M2 grade have been developed thermo-chemically. Thermo-chemical treatment was carried out after full heat treatment and included holding for 1 and 3 h at 550°C in order to produce different C-B-N diffusion layers. The microstructure and component depth profiles in the C-B-N diffusion layers were studied by scanning electron microscopy and energy dispersive X-ray spectrometry. It was shown that well adhered (diffusion controlled) carbon-boron-nitrogen layers with nanosized microstructure can be thermo-chemically developed at 550°C for 1 h on the wrought and as-cast M2 high-speed steel substrates. In the samples made of the wrought M2 high-speed steel and held at 550°C for 3 h the C-B-N diffusion layer develops in the fiber-like morphology.