Journal of the American Ceramic Society, Vol.85, No.5, 1133-1138, 2002
Preparation of titanium nitride/alumina laminate composites
A preparation route for TiN/Al2O3 laminate composites has been described. A water-based process using Al2O3 and TiN slurries with solids contents of 40 and 35 vol%, respectively, was used to make TiN and Al2O3 tapes. The removal of the binder was monitored by weight-loss measurements in a thermogravimetry unit. Bodies composed of Al2O3 and TiN tapes were densifted at temperatures of 1400degrees and 1500degreesC using the Spark Plasma Sintering(R) (SPS) technique. Densities of >98% of the theoretical densities were approached. Crack-free and almost fully densified TiN/Al2O3 compacts were prepared by heating the burned-out green bodies to the final sintering temperature (1500degreesC) at a rate of 100degreesC/min, and with a holding time of 5-10 min, under a pressure of 75 MPa. The microstructures of the obtained compacts were studied using scanning electron microscopy. Grain sizes in the sintered Al2O3 and TiN compacts were similar to those of the precursor powders. Hardness and indentation fracture toughness were measured at room temperature, and the monolithic compacts as well as the laminate composites exhibited anisotropic mechanical behavior; i.e., the cracks propagated much more easily in a direction parallel to the laminas than perpendicular to them.