Infrared spectra and structure of Si3N4, Si2ON2, and sialons

Abstract

Sialon powders are prepared from Kyshtymskoe kaolin with 12 – 28 wt.% carbon mixtures by the carbothermal reduction-nitridation method. The infrared spectra of β-, O′-, C- and 15R-phases in the Si – Al – O – N system are recorded and compared with the IR spectra of Si3N4, Si2ON2, and kaolin. The IR data are shown to correlate with the chemical composition of sialons and provide information supplementary to x-ray phase analysis data. The spectra of sialon powders differ from each other and from the spectrum of silicon nitride.