XPS/XAES study of carbon fibres 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° C to 300° C, 600° C, and 800° C, and then cooled at 25° C. The fibre status at each temperature step was monitored by analyzing the Cls, Ols, C-KVV, and VB regions. The decrease in concentration of oxygen-containing surface functional groups was pre sumably 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 lineshape of the Cls region of “oxygen-free” carbon fibres to be obtained.