Combustion Synthesis of MgSiNsub2/subPowder at Different Nitrogen Pressures

摘要

MgSiN2 powders have been synthesized by combustion synthesis (CS) using Mg and Si3N4 as starting materials at different nitrogen pressures. The CSed powders were then sintered by spark plasma sintering (SPS) to obtain dense bulk MgSiN2 product. Analysis of the CSed powder using X-ray diffraction (XRD) revealed single-phase MgSiN2 was obtained by CS method. However, the CSed product can be divided into three distinct parts according to its color. Scanning electron microscopy (SEM) observation revealed the grain size and crystallinity decrease gradually from the center to the outer layer. Some small grains clustered together to form larger particles, and there were a large number of pores among the clusters. The grain size seemed increasing with the increase of nitrogen pressure. The bulk density of CS-SPSed MgSiN2 was 3.11 g/cm3, Vickers hardness was 1673.1 kgf/mm2, and thermal diffusivity was 8.718E−2 cm2/s.