Direct nitridation of molten Al(Mg,Si) alloy to AlN

Abstract

The growth of AlN rod-like crystals, successfully produced via direct nitridation of Al-alloy doped with 5 wt% Mg and 2 wt% Si at 1273 K is predominantly based on capillary mass-transfer phenomena, which occur through a network of micro-channels developed in the empty space among the AlN columnar crystals as well as the hollows inside these crystals. The diffusion of N 2 in the liquid alloy is the rate-determining step of the process. Mg and Mg 3N 2 resulting after nitridation maintain a very low partial pressure of oxygen during the entire process and favour the formation of AlN.