Preparation of fine silicon particles from amorphous silicon monoxide by the disproportionation reaction

Fine Si particles have been prepared by the disproportionation reaction of silicon monoxide (SiO), that is: 2SiO→Si+SiO2. Amorphous powders of SiO are heated between 900°C and 1400°C in a flow of Ar and the obtained specimens are analyzed by X-ray powder diffraction and high-resolution transmission electron microscopy. The treatments between 1000°C and 1300°C for more than 0.5 h result in origination of Si particles dispersed in amorphous oxide media. The particle size varies from 1–3 to 20–40 nm, depending on the heating temperature. Kinetic analyses of the reaction reveal that the activation energy is 1.1 eV (82.1 kJ mol−1). The specimens annealed above 1350°C changes into a mixture of Si and cristobalite, suggesting a solid state transformation in the surrounding oxides from the amorphous to crystalline states.