Growth mechanism of aluminum nitride whiskers prepared from a (glutarato)(hydroxo)aluminum(III) complex

Abstract

Aluminum nitride (AlN) whiskers were synthesized by calcining an Al(OH)(glutarate)· xH 2O complex without mixing any catalyst under a flow of nitrogen in the temperature range 1150–1600 °C and then burning out the residual carbon (by the so-called modified carbothermal reduction and nitridation method). At the very low reaction temperature of 1150 °C, the whiskers with a bead-necklace structure were obtained, showing the beginning step in formation of the whisker and with increasing the temperature, the morphology of the whisker became the shape of a six-sided prismatic needle with the axis of [0001] direction. It is concluded from the change of morphologies with temperature that AlN whiskers grow through both the primary nanometer-sized AlN particle-to-particle connection and the solid diffusion of the particle, the latter being operative at relatively high temperature.