Growth mechanism of crystalline SiAlON microtubes prepared by combustion synthesis

Abstract

Crystalline SiAlON microtubes have been prepared by combustion synthesis, and the growth mechanism of the microtubes is discussed. Two mechanisms are proposed for the formation of the SiAlON microtubes, viz. accumulation of tip concave effect of rod-like crystals and side-by-side coalescence of rod-like crystals. The growth of SiAlON microtubes can be favored by the special reaction condition in combustion synthesis, which is characterized by high reaction temperatures (>1900 °C), drastic heating rates (∼10³ °C s⁻¹), and a high N₂ pressure of 6 MPa. The microtube is a new crystal shape of SiAlON, and an investigation on its formation mechanism increases the knowledge on crystal growth of SiAlON materials.