Synthesis of MgSiN<sub>2</sub> Powders from the Mg-Si System

Abstract

Magnesium silicon nitride (MgSiN 2 ) was synthesized without any additives under a nitrogen gas flow (200 mL/min) using a nitriding method. The effects of temperature and holding time on its purity and morphology were investigated. A single-phase MgSiN 2 powder was obtained at 1350˚C for 1 h and 1250˚C for 11 h. However, the decomposition of MgSiN 2 occurred at 1450˚C, suggesting that the optimum temperature for the preparation of MgSiN 2 from Mg-Si system was 1350˚C. The phase purity, morphology, size of the product and elemental composition of the samples were detected by X-ray diffraction (XRD), scanning electron microscopy (SEM) and energy spectrometer (EDS), respectively. The evaporation of Mg and Si resulted in the formation of many voids in the blocky product. The temperature gradient promotes the growth of MgSiN 2 on the surface of massive products along the tip. The concentration gradient of Mg and Si vapors in the void resulted in the columnar growth of MgSiN 2 .

Combustion Synthesis of MgSiN<sub>2</sub> Powder at Different Nitrogen Pressures

“…MgSiN 2 is also considered to be a promising luminescent material for light emitting diode (LED) applications [10] [11]. MgSiN 2 can be prepared by various methods, such as carbothermal reduction [12], direct nitridation [13] [14] [15], hot-pressing [16], solvothermal method by the reaction of SiCl 4 , N 2 H 4 ·HCl and Mg [17], the solid-state metathesis route using SiO 2 and Mg 3 N 2 as reactants [18]. However, most of these methods usually require high-energy consumption, high-temperature, long-time treatment.…”