Production methods of Al2O3-TiC/TiCN composites

ABSTRACT Master of Science Thesis PRODUCTION METHODS OF AI2O3-TİCAIİCN COMPOSITES ERHAN AYAS Anadolu University Graduate School of Natural and Applied Science Ceramic Engineering Program Supervisor : Assist Prof. Dr. Alpagut KARA 2003, 61 pages Alumina cutting tools are using in machining operations since 1930's. The fracture toughness of pure alumina is poor along with low thermal conductivity. Different types of additives are used to alumina to improve these properties. The most common additives are TiC and TiCN materials which have superior high temperature properties, high hardness and fracture toughness. Unfortunately previous studies showed that AI2O3- TiC/TiCN composite materials can not be sintered to their theoretical density with traditional sintering techniques. In this study different amounts of TiC and TiCN were added to AI2O3 by weight and the obtained compositions were sintered with pressureless and gas pressure sintering techniques. The physical properties like hardness and fracture toughness of the sintered products were examined. In addition, X- ray diffraction (XRD) and scanning electron microscope (SEM) techniques were used to achieve phase and microstructural characterisation. In both sintering techniques the density values are increased with the increasing of sintering temperature but in gas pressure sintering above 1750°C, decreasing of density values and the detonation of the products are observed. Keywords : Composite, AI2O3-TİC/TİCN, Pressureless Sintering, Gas Pressure Sintering ? ? Vu4 \f&^*V*