Fine-Grained Si3N4-Containing Ceramics from Nanopowders

Abstract

Different compositions of SiAlON materials have been prepared from separate nanopowders and their composites: Si3N4 – AlN, Si3N4, Al2O3 and Y2O3, produced by the method of plasma-chemical synthesis. Compositions have been pressure-less sintered in nitrogen medium up to 1750°C with a heating rate of 10°C/min and holding time for 2 hours or by spark plasma sintering (SPS) in vacuum at 1700°C with a heating rate of 100°C/min and holding time of 5 min. The densification behaviour of the materials at these sintering conditions depends insignificantly on the powder composition. It is possible to obtain dense ceramic materials with relatively fine-grained structure (200-300 nm) from nanosized powders at relatively low temperatures (1400 - 1600°C) with good mechanical properties.