Nitrogenation Conditions for Mixed Silicon and Aluminum Alkoxide Xerogels

The conditions for beta-SiAlON to be prepared by reacting highly dispersed mixed silicon and aluminum alkoxide xerogels with molecular nitrogen at 1600-1700 degrees C are determined. The nitrogenation of mixed xerogels is shown to be due to the catalytic pyrolytic decomposition of hydrolysis products of silicon and aluminum alkoxides in a nitrogen atmosphere, namely, a mixture of alcohols that are adsorbed or chemisorbed on aluminosilicate xerogel particles. The pyrolysis of alcohols in a nitrogen atmosphere catalyzed by highly dispersed alumina yields hydrogen and carbon monoxide, which activate nitrogenation and affect the phase composition of the samples and change the sialon stoichiometry from beta-Si3Al3O3N5 to the 15R polytype.

Automated summary

The conditions for preparing beta-SiAlON by reacting highly dispersed mixed silicon and aluminum alkoxide xerogels with molecular nitrogen at 1600-1700 degrees C are determined. The nitrogenation of mixed xerogels is shown to be due to the catalytic pyrolytic decomposition of hydrolysis products of silicon and aluminum alkoxides in a nitrogen atmosphere, leading to a change in the sialon stoichiometry from beta-Si3Al3O3N5 to the 15R polytype.