Normally, Researchers use SEM or TEM image to get the details about the distributions of the filler in the matrix of a composite. Is there any other method to identify the distribution and dispersion of filler in the matrix.
Depending on the filler material, composite itself, sample size 3D X-ray tomography can be a choice. It can be used to do virtual x-section and image processing software can be utilized to quantify the filler distribution. Again, it will depend on the material properties.
If you have thin enough sections you may see something on optical miscroscopy as well, or in reflection mode on polished sections. But the resolution is much worse than with SEM.