Phase Composition and Physicomechanical Properties of β-Sialons Prepared Using NaF as a Sintering Aid

We have studied the effect of sodium fluoride as a sintering aid for β-sialons on the phase composition and physicomechanical properties of Si₅AlON₇ and Si₄Al₂O₂N₆. Two-step high-temperature firing of the β-sialons in the presence of NaF under a nitrogen atmosphere has been shown to cause no significant changes in the phase composition of the materials. The density and microhardness of the materials prepared using 0.5 and 5.0 wt % NaF are lower than those of the materials prepared without sintering aids, but the bending strength is higher by up to 14.3% in the case of Si₅AlON₇ prepared using 0.5 wt % NaF and by 4.9% in the case of Si₄Al₂O₂N₆ prepared using 5.0 wt % NaF.