Carbon Fibers electron diffraction

Figure IS. Size and distortion separation. Integral breadth iss against l2 for the 001 reflections of carbon fiber and graphite whisker. Electron diffraction traces with 001 reflections resolved from hkO reflections.

As far as we know, apart from a preliminary report about mercerization of cotton fibers (3) and a recent paper about chemically etched PETP filaments (4), high modulus aramide fibers and carbon fibers are practically the only systems with detailed (recently) published work on electron diffraction and dark field of ultrathin sections of textile or paratextile fibers (5, 6,... 

The carbon fiber support and the catalysts before and after reduction were characterized with various techniques, viz. X-ray diffraction (XRD), transmission electron microscopy (TEM), scanning electron microscopy (SEM), temperature programmed reduction (TPR), Nz-physisorption, inductively coupled plasma emission spectrometry (Vista AZ CCD simultaneous ICP-AES) and hydrogen chemisorption. 

Carbon fibers scatter both x-rays and electrons, and the corresponding diffraction patterns can be used to assess structural parameters [4] [31]. The diffraction patterns of carbon fibers contain a limited number of reflections, i.e., usually a strong 002 reflection and (when present) weaker 004,10 and 11 reflections, due to the turbostractic character of the carbon. The OOl and hk reflections become less dif se as the heat treatment temperature (HTT) is increased. Finally, the separation of the 10 reflection into its 100 and 101 components and the appearance of the 112 reflection are observed only for true graphite fibers, prepared from mesopitch fibers and formed at 3000 C. 

Analytical Techniques. Analytical techniques to determine the structure of carbon fibers include wide-angle and small-angle x-ray diffraction, electron diffraction, neutron scattering, Raman spectroscopy, electron microscopy, and optical microscopy. Detailed reviews of these techniques are found in the literature. ... 

Composites may also be examined by transmission EM methods, such as by bright field, dark field and electron diffraction of ultrathin sections. Sections of carbon fiber composites are quite difficult to obtain, but the technique is possible and has been described by Oberlin [309, 310]. Important information that can be obtained relates to the fiber-resin interface which is known to be critical to composite properties and is often adversely affected by environmental conditions. 

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