Formation of α-Si 3N 4 whiskers with addition of NaN 3 as catalyst

Abstract

α-Si 3N 4 whiskers with diameters of about 0.1 μm and length of 3–5 μm were fabricated through combustion synthesis route under very low nitrogen pressure of 0.5–1 MPa. The measured maximum combustion temperature is about 1863 K which is rather lower than the adiabatic temperature (about 4400 K) and the decomposition temperature (about 2170 K) of Si 3N 4 under atmospheric pressure. The addition of NaN 3 catalyst plays a key role in the formation of α-Si 3N 4 whiskers under such low nitrogen pressure.