Elucidation of the Formation Mechanism of β‐SiAlON from a Zeolite

β‐SiAlON was synthesized from Y‐type zeolite and its formation mechanism was determined using magic‐angle spinning nuclear magnetic resonance (NMR) spectroscopy and powder X‐ray diffraction (XRD). Y‐type zeolite and carbon powders were mixed for 36 h, fired at 1050° to 1450°C for 0–2 h in flowing gas (0.5 L/min N 2 ), then heat treated at 700°C for 2 h in air to remove residual carbon. The resulting product was, according to XRD analysis, mono‐phase β‐SiAlON; but minor amounts of unreacted SiO 2 and SiC (possibly amorphous) were detected in the NMR spectra. It was found that β‐SiAlONs with higher and lower Z values are formed by different reaction pathways.