HRTEM and ELNES analysis of polycarbosilane-derived Si-C-O bulk ceramics

A series of analyses by high-resolution transmission electron microscopy (HRTEM) and electron energy-loss spectroscopy (EELS) has been carried out to investigate the nanostructure and the chemical bonding of Si-C-O bulk ceramics prepared by pyrolysis of oxygen-controlled polycarbosilane (PCS). HRTEM revealed that the Si-C-O ceramics with higher oxygen content tended to keep an amorphous microstructure. EELS allowed the examination of energy-loss, near-edge-structures (ELNES) that detected clear transition signals of the chemical bonding around Si atoms from Si-C bonding to Si-O bonding with an increase of oxygen content. The microstructure of the PCS-derived Si-C-O bulk ceramics is characterized as a function of oxygen content. (C) 2000 Elsevier Science B.V. All rights reserved.