Spark plasma sintering of silicon nitride/barium aluminum silicate composite

Si3N4 based composites were successfully sintered by spark plasma sintering using low cost BaCO3, SiO2 and Al2O3 as additives. Powder mixtures were sintered at 1600-1800 °C for 5 and 10 min. Displacement-temperature-time (DTT) diagrams were used to evaluate the sintering behavior. Shrinkage curve revealed that densification was performed between 1100 and 1700 °C. The specimen sintered at 1700 °C showed the maximum relative density (99.8±0.1%), flexural strength (352±16 MPa), Vickers harness (11±0.1 GPa) and toughness (5.6±0.05 MPa m1/2).