Preparation of Ni-Mo-C/Ti(C,N) coated powders and its influence on the microstructure and mechanical properties of Ti(C,N)-based cermets

Ni-Mo-C/Ti(C,N) coated powders, namely Ni-Mo alloy and Mo2C coated Ti(C,N) composite powders, were synthesized by using a heterogeneous precipitation and thermal reduction method, then pressed and vacuum sintered to fabricate cermets. The chemical composition, microstructure and phases of the composite powders and the microstructure and properties of sintered cermets were experimentally investigated. The results show that a fine and uniform microstructure of (Ti,Mo)(C,N)-Ni cermets without the conventional core-rim structure is obtained. The phases formed during the preparation of the coated powders as well as the cermets were analyzed by means of a X-ray diffraction (XRD) technique. The XRD result confirms the formation of the Ni3Ti phase in the cermets. Due to the formation of the non-magnetic Ni3Ti and the dissolution of Mo in Ni binder phase, the magnetic properties are strongly retarded. The fracture of the cermets is mainly characterized by intergranular and dimple fractures. Better mechanical properties can be obtained in comparison with conventionally fabricated ones. (C) 2015 Elsevier Ltd and Techna Group S.r.l. All rights reserved.