Alumina-Silicon carbide laminated composites by spark plasma sintering

Dense and compact SiC-Al2O3 composite laminates were obtained in the present work by Spark Plasma Sintering (SPS). Green ceramic layers consisting of different mixtures of alumina and silicon carbide were produced by tape casting; these were then stacked together and cosintered by SPS to produce monolithic composite disks with loads of SiC from 0 to 30 vol%. An engineered laminate with a specific architecture (i.e. layers combination) able to promote the stable growth of surface defects was also designed and fabricated. Fully dense materials with optimum adhesion between constituting layers were obtained after SPS. Monolithic composites showed an increasing strength with SiC load and biaxial strength values as high as 700 MPa were obtained for SiC content of 30 vol%. The engineered laminate showed a graceful crack propagation that is responsible for the high strength value (≈600 MPa) and for a certain insensitiveness to surface defects.