Ab initio and experimental study on the mechanism of Al4C3 nitridation in vacuum to prepare AlN

Aluminium nitride has good electrical, thermal, and mechanical properties, and Al4C3 is the most important intermediate in the preparation of AlN through carbothermal reduction. Ab initio molecular dynamics (AIMD) simulations were adopted in this study to elucidate the nitridation reaction mechanism of Al4C3, and an experimental study was conducted to verify the results of AIMD. Both the AIMD and experimental results showed that the nitridation pathway of Al4C3 was Al4C3→Al5C3N→AlN and that the nitridation of Al5C3N was considerably rapid. During the nitridation of Al4C3, the addition of carbon not only had a catalytic effect on the activation of nitrogen molecules but also promoted the aggregation of carbon atoms in the Al4C3 lattice to form elemental carbon.