Structural and Microstructural Properties of Si-C and Si-C-B Powders Obtained by High-Energy Ball Milling

This work evaluated on the structural modification during high-energy ball milling of the Si-50C, Si-42.9C-19.1B e Si-33.3C-44.4B (at.-%) powder mixtures from elemental powders. Electron images revealed on occurrence of continuous fracture mechanisms in brittle particles during their processing, which presented rounded particles lower than 10 μm. X-ray diffraction results of Si-50C powders indicated that the intensity of Si peaks was slightly reduced after milling for 17 h, which were moved to the direction of larger diffraction angles after 7 h of milling, suggesting that carbon atoms were dissolved into the Si lattice in order to form an extended solid solution. Following, these values were increased due to the discrete exothermic formation of the SiC compound. In Si-C-B powder mixtures, the SiC and B4C compounds were formed after milling for 7 h.