Characterization of the chemical bonding in inner layers of composite materials.

The efficiency of near edge structure investigations in electron energy loss spectroscopy (EELS) is discussed for characterizing the chemical bonding of elements present in the interfacial zone in fibre/matrix composites at nanometre resolution. Two different examples of corresponding analyses are given for a SiC-fibre reinforced borosilicate glass. In particular, the chemical bonding between silicon and carbon or oxygen (e.g. SiC, SiO(2) and SiO(x)C(y)), respectively, is characterized. The results have been attained in a fingerprint manner by comparing the fine structure measured from a material of unknown stoichiometry to that of a standard specimen. In addition, a possibility is demonstrated to image the chemical bonding by energy-filtered microscopy using energy loss near edge structures (ELNES).