This work investigated the role of NbC on densification, grain growth, and properties of WC-10AISI304 hardmetals sintered by a pseudo hot isostatic pressing process at 1300 °C under vacuum with a pressure of 20 MPa. In this study, in addition to 2 wt.% graphite to reduce the presence of η-phase (Fe3W3C or M6C) during sintering
1, 1.5, 2 or 5 wt.% NbC was added to a powder mixture of WC-10AISI304. Pseudo hot isostatic pressing enabled densification of the hardmetals, forming more η-phase than with vacuum sintering alone. The addition of NbC leads to a decrease of WC grains and reduces the formation of η-phase during sintering. Elemental analysis showed that a high content (5 wt.%) of NbC encouraged the formation of coarse (Nb, W)C grains, resulting in decreased hardness. Addition of 2 wt.% NbC exhibited the highest Vickers hardness (1820 kg/mm2) with moderate fracture toughness (about 7.7 MPa.m1/2) by encouraging refinement of hardmetal grains and limiting the formation of η-phase during sintering. © 2012 Elsevier B.V. All rights reserved.