Modification of WC hard alloy by compressive plasma flow

Abstract

The effect of compressive plasma flows of nitrogen on the mechanical properties, phase and element composition of a WC hard alloy (6 wt.% of Co) has been investigated in this work. Compression plasma flows were obtained using a quasistationary plasma accelerator. X-ray diffraction analysis, Auger electron spectroscopy, scanning electron microscopy and X-ray microanalysis were used as investigation techniques.It was found that the whole depth of the modified layer amounted to 15 μm. The phase composition analysis showed that plasma treatment resulted in the transformation of a WC phase into a W2C one. The formation of a graphite phase was also found in the surface layer. The element composition analysis revealed surface segregation of carbon and cobalt. The findings also showed that microhardness of the hard alloy increased 1.7 times after treatment.