Synthesis and thermal stability of nanocrystalline chromium disilicide

摘要

Nanocrystalline chromium disilicide was synthesized by co-reducing anhydrous chromium trichloride and sodium fluorosilicate with metallic potassium at 650 deg C in an autoclave. X-ray powder diffraction pattern indicated that the product was hexagonal CrSi_2. Transmission electron microscope images showed that the sample consisted of particles with the diameters of 20-50 nm and an average diameter of about 35 nm. TGA and DTA indicated that the oxidation of CrSi_2 began to proceed at 700 deg C in air, and only about 8.6 wt. percent of the sample was oxidized in the surfaces of the particles below 1000 deg C. It had high thermal oxidation stability due to the formed protective layer.