Phase composition and morphology of the products of ferrosilicon burning in nitrogen

The results of a study of the phase formation of silicon nitride during the combustion of ferrosilicon in gaseous nitrogen are presented. It is shown that the formation of a- or b-modifications of silicon nitride is mainly determined by the composition of the charge for self-propagating high-temperature synthesis. When ammonium chloride is introduced into the initial ferrosilicon, a combustion product is formed with an increased (up to 80%) content of a-Si ₃ N ₄ , while dilution with the final product and magnesium fluoride results in to the formation of predominantly (more than 95%) b-Si ₃ N ₄ . The size and shape of the particles depend on the synthesis conditions and are primarily determined by its temperature and the additives introduced into the initial alloy. Il. 3, bibliography: 8 titles.