Abstract
The ancient iron specimens are known to be highly corrosion resistant compared with the nowadays blast furnace iron. In the case of Japanese nail prepared by "Kaji", the surface is covered by the oxide film which has grown at the forging.
In this work, to make how Japanese nail keeps high corrosion resistance clear, the structure characterization of the oxide film grown over the nail used at Bicchu-kokubun-ji temple by electron diffraction method was attempted. The blast furnace iron was also similarly examined for comparison.
The main results obtained as follows:
(1) Japanese nail contained in quantity of non-metallic inclusion, mainly wustite (FeO) and silicate, was covered by dense and minute poly-crystal oxide film which the thickness was about 4 pm,
(2) The crystal unit size of the FeO was about 10nm,
(3) While the FeO grown on the blast furnace iron was mono-crystal and the crystal unit size was about 3 pm.
