Contrast-matching small-angle neutron scattering has been performed on Pittsburgh No. 8 coal in a mixture of H2O and D2O. Pycnometric and swelling experiments showed that in the time scale of the experiment there was no overall sorption of water by the coal. The effect of contrast matching was to reduce the value of the scattering Porod invariant by more than one order of magnitude. Scattering from the contrast-matched sample was interpreted to mean that Pittsburgh No. 8 coal had very low levels of porosity.
- neutron scattering