EFFECT OF CARBON CONTENT ON SINTERABILITY AND PROPERTIES OF ZrO_2 DOPED WC-CERMETS

摘要

The control of carbon amount has an important role in controlling the mechanical properties of cemented carbides. In this study an integral effect of adding different carbon amounts in combination with three different sintering techniques was investigated. Graphite was used as carbon source and was added to the WC - 8 wt.% Ni - 6 wt.% ZrO_2 mixture in 0 wt.% C, 0.2 wt.% C, 0.4 wt.% C, 0.7 wt.% C and 1 wt.% C in order to reveal influence of carbon amount on the mechanical properties and microstructure of the composites. The composite with 0.2 wt.% C showed the highest density and hardness, ~ 100% T.D. and 1700-1800 HV20 respectively, for all sintering techniques. Increasing the amount of carbon further caused clear grain growth during hot isostatic pressing and vacuum sintering. In spark plasma sintering the grain growth was suppressed regardless of carbon addition.