Sintering a mixture of powders in the Al2O3-SiO2-P-SiAlON-TiC-Dy2O3 system by the plasma-spark method with the high compaction load

Abstract

The effect of the addition of 2 and 5 mol. % Dy₂O₃ during plasma-spark sintering at a pressing load of 60 MPa in the range of 1200—1600 °C for phase composition, microstructure, relative source, open porosity, linear shrinkage, physicomechanical properties, and linear correlation of the elastic modulus and toughness of mullite-sialon-TiC samples. The synthesized powders of sialon and TiC are characterized by corresponding intensive crystallization. The increase in the content of Dy₂O₃ from 2 to 5 mol. % in the sintered composition with the release of p-SiAlON / TiC = 70/30 mol. TiC in the range of 1200—1600 °C, also leading to the formation of less dense, crystalline microstructures that form titanium dioxide, round forms, pores and glassy phase at the interface of mullite-sialone-TiC solid solution at 1500 ^oC. Sample 5 mol. % Dy₂O₃ has lower values of relative density, linear shrinkage, physical and mechanical properties in the range of 1200-1600 °C, lower resistance to cracking with the formation of microcracks at 1500 °C and a slightly larger linear correlation of the elastic modulus and toughness in the range of 1200-1600 °C. Ill. 8. Ref. 13. Tab. 1.