Production OF Al2O3–Co-TiO2 Cermet by Spark plasma sintering

Ceramic-metal composites (Cermets), which are a well-known category of advance materials, attract so much interest during decades due to their excellent abrasion and corrosion resistance. Powder metallurgy is a suitable method for fabrication of such materials; however this route is accompanied with the non-uniform distribution of reinforcements in the matrix, high sintering temperature and advanced equipment required. In order to reduce such limitations, in the present study Al2O3-Co-TiO2 nano-cermets were fabricated by using metal coated TiO2 and Al2O3 powders. In this regard electroless cobalt deposition technique was used for metal coating of micronized Al2O3 particles, as well as TiO2 nanoparticles. Subsequently, different compositions of coated particles were used to fabricate variety of nano-cermets. In this investigation, spark plasma sintering (SPS) has been used, for obtaining fully dense nanocermets. The morphology and chemical composition of the Co-coated powders were characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive spectroscopy (EDS). The results showd uniform shells were coated on micronized Al2O3 particles, and TiO2 nanoparticles Also because of direct contact of Al2O3 and TiO2 particles was prevented in this method, sintering temperature of such cermets from sintering temperature of Al2O3 to sintering temperature of Cobalt decreases

Keywords:

nano-cermet , electroless , spark plasma sintering