Large‐Scale Synthesis of Magnenium Silicon Nitride Powders at Low Temperature

Magnesium silicon nitride (MgSiN2) powders have been synthesized by the reaction of SiCl4, N2H4·HCl, and Mg in an autoclave at 450°C for 5 h. The yield of the products is calculated to be about 90% according to the amount of SiCl4. X-ray powder diffraction patterns indicated that the products are orthorhombic MgSiN2 (cell parameters: a=5.252 A, b=6.426 A, and c=4.979 A) together with little amount of Si. The results of scanning electron microscopy and transmission electron microscopy (TEM) observations indicate that the particles have rough surfaces and have diameters in the range of 0.5–3 μm. The high-resolution TEM image shows clearly resolved fringes separated by 0.248 nm, which corresponds to the (002) d-spacing of the orthorhombic MgSiN2. The effects of different synthesis conditions on the final formation of MgSiN2 powder, such as the different ratios of the precursors, reaction temperature, and nitrogen sources were also investigated.