WC-reinforced (Ti,W)(CN)

A ceramic microstructure of WC-reinforced (Ti,W)(CN) was designed using thermodynamic instability among the constituent elements and gas species involved in the sintering process. During sintering WC in the shape of platelets formed in (Ti,W)(CN) solid-solution ceramics, which were synthesized from milled Mixtures of oxides with carbon. The WC platelets separated from the (Ti,W)(CN) ceramics due to the low chemical affinity of tungsten for nitrogen. The shape of WC varies depending on the composition of the binder phase and the sintering conditions. With increasing binder content, the WC platelet shape became more irregular. This change was attributed not only to surface energy but also to the formation mechanism. The presence of WC platelets toughened (Ti,W)(CN) significantly at excellent hardness value (H-v: 18.5-20.0 GPa, K-IC: 6.0-6.8 MPa m(1/2)) as compared to those of recently reported advanced structural ceramics. (C) 2009 Elsevier Ltd. All rights reserved.