HOT HARDNESS AND CREEP OF SI3N4 SIC MICRO/NANO-COMPOSITE AND NANO/NANO-COMPOSITE/

In the present study, mixtures of conventional alpha-Si3N4 with beta-S iC or nanosized beta-SiC and ternary Si-C-N (15-20 nm) powders without and with Y2O3/Al2O3 as additive were used as starting materials. By H ot Isostatic Pressing of these powders, micro/nano-composites and nano /nanocomposites were obtained. Dynamic hot hardness at 800, 1000 and 1 100 degrees C and creep behavior at 1600 degrees C for pressures of 50 ,100 and 150 MPa were used to characterize the materials. The influenc e of grain size and SiC content on these properties is discussed. (C) 1997 Acta Metallurgica Inc.