Conversion of Alumina to Aluminum Nitride Using Polymeric Carbon Nitride as a Nitridation Reagent

Polymeric carbon nitride, which was synthesized by polymerization of dicyandiamide at 500°C, was used as a nitridation reagent in the conversion of δ‐alumina (δ‐Al₂O₃) to aluminum nitride (AlN). The products obtained at various reaction temperatures were characterized by powder X‐ray diffraction, ²⁷Al magic‐angle spinning nuclear magnetic resonance (MAS NMR) spectroscopy, Raman spectroscopy, and X‐ray photoelectron spectroscopy (XPS). δ‐Al₂O₃ began to convert to AlN at 900°C, which is the lowest temperature reported for the formation of AlN from Al₂O₃, and completely converted to AlN at 1400°C. The occurrence of reaction intermediates during nitridation was confirmed by ²⁷Al MAS NMR and XPS. The change in Raman spectra with reaction temperatures indicated that lattice defects in AlN were reduced by calcining at higher reaction temperatures.