Synthesis of Functional Materials by Means of Nitriding in Salts of Al2O3–Al, Al2O3–Ti and Al2O3–Fe Cermets

Abstract

ABSTRACTIn this work the synthesis of functional gradient materials (FGMs) through the nitriding in salts of previously fabricated cermets is carried out. The matrix for the preparation of the FGMs is made of an Al2O3-based cermet with a fine and homogeneous dispersions of metallic particles of Al, Ti and Fe, the final content of the metallic particles in the cermets is of 10 vol. %. These materials are synthesized by powders techniques, considering as variable of study the reinforcement metal in the cermet, previous to sinter, cylindrical samples of the corresponding cermet are uniaxially compacted using 200 MPa. Subsequently, all sintered cermets are characterized by microstructural observations with the help of light microscopy. Obtained cermets are then submitted to a nitriding process by immersion in ammoniac salts. The objective is to attain a compositional gradient of metal-nitrides at the surface. This is done through a chemical reaction between the metallic particles at the cermets' surface and the nitrogen released by the ammonia salts. Functional materials are obtained such as; Al2O3–Al–AlN and Al2O3–Ti–TiN.