Phase composition of the combustion products upon ferrosilicon burning in nitrogen with F-containing additives present

The effect of fluorine-containing additives (ammonium fluoride and topaz concentrate) on the phase composition of the combustion products of ferrosilicon in nitrogen and the morphology of particles of the resulting silicon nitride is investigated. It is shown that the introduction of topaz concentrate into ferrosilicon in an amount of 0.5% transforms the self-oscillating combustion mode, characteristic of nitriding ferrosilicon without additives, into a layer-by-layer one. It was found that in the presence of ammonium fluoride, a high-temperature & # 946; -modification of silicon nitride & # 946; -Si ₃ N ₄ is formed, and in the presence of topaz concentrate, a solid solution on based on & # 946; -Si ₃ N ₄ type SiAlON. Tab. 1, ill. 3, bibliography: 7 titles.