Abstract
AlN fine particles were prepared by gas-phase reaction of AlCl3 and NH3in ultrasonic fields. Using experimental runs in a vertical tubular-flow reactor of 50 mm inner diameter, the effects of ultrasonic sound pressure, concentration of AlCl3and reaction temperature were investigated.
In the operating range of sound pressure (Ps=24-115Pa) measured at room temperature, average particle sizes decreased exponentially with increasing sound pressure. It was revealed that, under constant reaction temperature conditions, particle size became larger in proportion to 0.44 power of AlCl3 concentration. The concentration dependency of the particle size showed fairly good agreement with the correlation of Lai et al., which was derived for particle growth. With respect to reaction temperature, particle size decreased with temperature below about 1100 °C and then increased up to 1302 °C. Compared with the ordinary preparation method by gas-phase reaction, the sizes of particles prepared at a pressure of 115 Pa were always about 32 % smaller within the present AlCl3 concentration range of 1.04.4 mol/m3 or reaction temperatures of 8701302 °C.
