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 degreesC and 1400 degreesC 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 degreesC and 1300 degreesC 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 degreesC changes into a mixture of Si and cristobalite, suggesting a solid state transformation in the surrounding oxides from the amorphous to crystalline states. (C) 2001 Elsevier Science B.V. All rights reserved.