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Nanocrystalline chromium disilicide was synthesized by co-reducing anhydrous chromium trichloride and sodium fluorosilicate with metallic potassium at 650 °C in an autoclave. X-ray powder diffraction pattern indicated that the product was hexagonal CrSi2. 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 CrSi2 began to proceed at 700 °C in air, and only about 8.6 wt.% of the sample was oxidized in the surfaces of the particles below 1000 °C. It had high thermal oxidation stability due to the formed protective layer. [Copyright &y& Elsevier]

Nano-crystalline vanadium disilicide was successfully synthesized using vanadium tetrachloride and silicon as starting materials via reduction–silication route at 650 °C in the molten salt solution of magnesium chloride and sodium chloride in an autoclave. X-ray powder diffraction patterns indicated that the product was hexagonal VSi2 (a=4.572 A˚, c=6.372 A˚). Transmission electron microscopy images showed that the particle size of the product was in the range of 40–60 nm in diameter. There was a strong absorption peak at 271 nm in the UV-Vis absorption spectra. The oxidation of nano-crystalline VSi2 began to proceed at the temperature of 400 °C in air. But the product had high thermal oxidation stability below 1000 °C. It can be used as an antioxidation coating material. [Copyright &y& Elsevier]