High-quality cemented carbides on the basis of near-nano and coarse-grain WC powders obtained by self-propagating high-temperature synthesis (SHS)

Abstract

In the present paper cemented carbides with different grain sizes produced with WC powders obtained by the self-propagating high-temperature synthesis (SHS) were examined. Morphology, particle size distribution and chemical composition and of the SHS-powders were studied in detail. Microstructures of a submicron grade with 5% Co made from the near-nano WC powder obtained by the SHS and a standard submicron grade are similar with slightly more large WC grains in the sample made from the SHS WC powder. The mechanical properties of the ultrafine WC–5% Co grade made from the near-nano WC powder obtained by the SHS and its wear-resistance are comparable with those of the standard ultrafine grade. The microstructure of a medium-coarse WC–6% Co grade made from the medium-coarse SHS WC powder and its properties are comparable with those of the convenient medium-coarse carbide grade for percussive drilling. Results of laboratory performance tests on percussive drilling of the medium-coarse WC–6% Co grade obtained from both the SHS WC powder and conventionally fabricated WC powder indicate that their wear-resistance and performance toughness are very similar. Thus, it is established that high-quality WC–Co cemented carbides with different WC grain sizes varying from submicron to medium-coarse can be produced from the SHS WC powders.