Corrosion investigation for iron artifacts dug out at the 6th Yamato ancient tomb

We analyzed corrosion depth for some iron artifacts dug out at the 6th Yamato ancient tomb in Nara prefecture using X-ray CT for the purpose of estimation for long stability of iron material in the ground as a part of the natural analog study related to the research of the high-level nuclear waste disposal. These samples are three big and 17 small iron artifacts which are called 'Tetsutei' like as horseshoe iron plate. It is considered that the most of them had been buried in a slightly oxidizing or reducing environment. The analysis result shows the maximum corrosion depth is 1.6 mm for about 1500 years. This paper presents an outline of this study. (author)