XPS XAES STUDY OF CARBON-FIBERS DURING THERMAL ANNEALING UNDER UHV CONDITIONS

High-modulus, polyacrylonitrile-derived carbon fibres were heated in situ, in the analysis chamber of an XPS spectrometer, from 25-degrees-C to 300-degrees-C, 600-degrees-C. and 800-degrees-C, and then cooled at 25-degrees-C. The fibre status at each temperature step was monitored by analyzing the C1s, O1s, C-KVV, and VB regions. The decrease in concentration of oxygen-containing surface functional groups was presumably responsible for most of the changes in the examined spectral regions. The analysis of the results did not give evidence of any change in the carbon sp2 bonding, and allowed a reasonably accurate line-shape of the C1s region of "oxygen-free" carbon fibres to be obtained.