Rheological characterization of β-siafon and Si3N4 slips and fabrication of multilayered composites by slip casting

摘要

Layered composites have been studied extensively in recent years because of their unique properties [1-8], Improvement of fracture strength by the surface compressive stress is one of the characteristic features of the layered composites, e.g. (SiC + 10%AiN)/(SiC + 50%AiN) three layered composite [1] and (A12O3 + ZrO2 (unstabilized))/(Al2O3 + Z1O2 (stabilized)) three layered composite [2-4]. The other feature is non-linear fracture behaviour similar to the long-fibre composites, e.g. AI2O3 multilayered composite [5], A12O3/ 3Al2O32SiO2 multi layered composite [6] and SiC-whisker/Si3N4 multilayered composite [7]. Particularly, we have focused on β-sialon (Si6_zAlzOzNg_Z) with z = 0 to 4.2)/Si3N4 layered composite because the fracture strength was improved by the thickness control of the surface β-sialon layer [8] and high oxidation resistance is expected due to the surface β-sialon.