Combination of Colloidal Techniques and Powder Metallurgy for Processing Fe-Ti(C,N) Cermets

摘要

Cermets constituted by a high-speed steel matrix reinforced with 50 vol% TiCN present a greatpotential due to its combination of properties, such as high wear and oxidation resistance, togetherwith high values of hardness and toughness. However the conventional powder metallurgy (CPM)processing presents two main problems: 1) The trend to agglomeration of TiCN particles, leading tonon-homogeneous microstructures, 2) the low compressibility of blendings due to the small size andmorphology of the particles of the starting powders. In this work, colloidal techniques are proposed toovercome these issues. Aqueous suspensions of steel powders and Ti(C,N) particles are preparedfollowed by spray-dry to obtain spherical granules able to be processed by pressing and sintering,avoiding oxidation of powders. The agglomerates present higher compressibility than blendings, andsintered materials show higher density and hardness.