Spectrum generated from the pixels representing SiC fibers. Figure 3 shows the fibers with the outer layer in white. Clearly, the erosion process can be repeated. Thus a profile across the fibers reveals composition as a function of distance from the surface. Fiber regions displayed with the outer layer of pixels in white.
Sequential erosions can peel away the outer layer one pixel depth at a time.
If the pixel resolution is chosen to match the X-ray range, operations such as erosion or dilation yield elemental information on the same scale. With the capability of most modern SEMs to produce good images at low voltage, X-ray spatial resolution has never been better. Figure 4 shows a plot of the number of counts in the oxgyen window after successive erosions. Note that there are three data points in less than the outer one micrometer. In this case, the oxygen was measured radially inward on ceramic fibers, but the technique works on any shape that can be delineated.