Fabrication of β-Si3N4 whiskers from a GPSed-RBSN sponge using 6Y2O3–2MgO additives

In this study, β-Si3N4 whiskers with a diameter of 0.05–1.5 μm and length of about 70 μm were successfully fabricated using a gas pressure sintered (GPSed)-reaction boned silicon nitride (RBSN) process at 1550 °C for 9 h. The β-Si3N4 whiskers grew on the frame and filled fully in the pores of the GPSed-RBSN sponge. 6Y2O3–2MgO additives played a significant role in the growth of β-Si3N4 whiskers and α-Si3N4 whiskers, while α-Si3N4 whiskers, which were grown inside the RBSN sponge through the vapor–solid mechanism, had a diameter ranging from 50 to 100 nm and length of about 80 μm.