Stray field magnetic resonance imaging (STRAFI) of water transport in ceramic substrates

Measurements of water transport in ceramic tiles made using the stray field magnetic resonance imaging technique (STRAFI) are reported. STRAFI represe nts one method of accomplishing magnetic resonance imaging (MRI) of solids and confined liquids. Water was demonstrated to saturate a sample, cored from an unglazed wall ti le, within 4 minutes of exposure. The sample was in constant contact with w ater at the upper surface and open to air at the bottom. The water ingress was characteristically Fickian in its dynamics. Samples cored from glazed w all and floor tiles were demonstrated to be waterproof (down to 50 mum spat ial resolution) up to 20 h. Water was shown to ingress samples from abraded , glazed floor tiles, in which the glaze layer was damaged. In this situati on, a dynamic equilibrium was established between water entering the upper surface and evaporating from the bottom surface. A gradient of water conten t through the tile developed. These observations held not only for the abra ded tiles, but also for certain household tiles of lower porosity than the unglazed wall tile.