posted on 2021-04-07, 18:08authored byJochen A. H. Dreyer, Carsten Gundlach, Claus E. Weinell, Kim Dam-Johansen, Søren Kiil
In this study, a rapid and versatile
methodology for quantitative
pore structure characterization is described taking the example of
intumescent char. The char porosity and pore structure tend to be
difficult to quantify but are decisive for the material’s thermal
conductivity and thus performance. The methodology described here
uses a fluorescent dye containing epoxy to impregnate the char. After
curing, the sample is cut and polished, followed by imaging with a
fluorescence microscope. The recorded images are segmented using an
open-source interactive machine learning program, followed by automated
pore size and porosity measurements. Volume-based three-dimensional
(3D) pore size distributions are calculated via stereography and compared
to X-ray microcomputed tomography (μ-CT) results. The pore aspect
ratio and tortuosity of the solid char phase are also discussed. It
is shown that the fluorescence microscopy methodology produces high-resolution
images with excellent contrast, while similar pore metrics (porosity
of 81.8%, average volume-based pore size of 70.5 μm) to those
for μ-CT are obtained.