Evaluation of carbon films on the Japanese smoked roof tile “Ibushi-Kawara” by angle-dependent soft X-ray emission spectroscopy using synchrotron radiation

Surface carbon films on the Japanese smoked roof tile “Ibushi-Kawara” (hereafter “Kawara”) were analyzed by angle-dependent soft X-ray emission spectroscopy using synchrotron radiation. The carbon film microstructure on typical Kawara is 50% carbon-black-like sp2 carbon atoms, which form layer-structured clusters parallel to the basal clay plane, and 50% carbon-black-like atoms, which form random-structured clusters that rigidly connect the layer-structured clusters. Weathered Kawara that has been exposed to sea breezes for numerous years was analyzed to understand the weathering effect from a microstructure point of view. The main weathering effect was the removal of the carbon film. It was also determined that the black stripes, which appear on the degraded “Susumaki” Kawara, are made from random-structured carbon black.