Study of amorphous compounds obtained by ball milling in the Si-C-O system

Generally, the Si-C-O system is composed Of SiO2, SiC, and pure C as crystalline phases. In the present study, we focus on the preparation of ternary silicon oxycarbide compound. For this purpose, different mixtures of quartz, silicon, and graphite were ball milled to cover the following range of composition: (1) SiCxO2(1 - x) + excess of C; (2) SiCxO2(1 - x) stoichiometric; (3) SiCxO2(1 - x) + excess of Si. The course of the reaction is followed by X-ray diffraction, by measuring the relative intensity change of the Bragg's peaks as a function of the mechanical treatment. The Rietveld method is applied to the patterns for quantitative analysis and determination of crystallite size and microstrain. Finally, the behavior of each phase is reported across the three starting compositions examined here and the presence of silicon oxycarbide compounds induced by ball milling is assessed by [Si-29-MAS]NMR.