NOVEL TECHNOLOGY FOR X-RAY MAPPING OF CERAMIC MICROSTRUCTURES

Field-emission scanning electron microscopy (FESEM) nas coupled with a technology called position-tagged spectrometry (PTS) to characterize the microstructure of a ceramic-matrix composite at the submicrometer level. Low-voltage microscopy with an FESEM microscope achieves both h igh-resolution imaging of uncoated ceramic specimens and submicrometer X-ray resolution with minimal specimen charging. The PTS technology i nvolves scanning the electron beam and collecting X-rays, as in mappin g; however, in this case, the X-ray photons are tagged with position i nformation. X-ray maps and full spectra were reconstructed from discre te parts of the composite. The distribution of oxygen within the fiber s was measured and found to decrease from the surface to the interior. The composition and phase distribution of the matrix were also reveal ed at high resolution, and the phase compositions were quantified.