Formation Mechanism of High-Purity Ti(2)AlN Powders under Microwave Sintering

In the present study, high-purity ternary-phase nitride (Ti(2)AlN) powders were synthesized through microwave sintering using TiH(2), Al, and TiN powders as raw materials. X-ray diffraction (XRD), differential scanning calorimetry (DSC), transmission electron microscopy (TEM), and scanning electron microscopy (SEM) were adopted to characterize the as-prepared powders. It was found that the Ti(2)AlN powder prepared by the microwave sintering of the 1TiH(2)/1.15Al/1TiN mixture at 1250 °C for 30 min manifested great purity (96.68%) with uniform grain size distribution. The formation mechanism of Ti(2)AlN occurred in four stages. The solid-phase reaction of Ti/Al and Ti/TiN took place below the melting point of aluminum and formed Ti(2)Al and TiN(0.5) phases, which were the main intermediates in Ti(2)AlN formation. Therefore, the present work puts forward a favorable method for the preparation of high-purity Ti(2)AlN powders.