New approach to the elucidation of corrosion mechanism of ceramics by the ion implantation

Saito, Junichi  ; Tachi, Yoshiaki  ; not registered; Kano, Shigeki

Ceramics possessing high temperature strength are promising matelials for the structural application in severe environment. The development of ceramics has been carried out in order to use them in FBR environment such as liquid sodium. In particular, corrosion behavior of ceramics has been investigated to improve the corrosion resistance in liquid sodium. However, the corrosion mechanism of ceramics was not comprehended in detail even now. Because corrosion products which were deposited on the surface of test pieces a during corrosion test and played an important role in corrosion behavior were not detected distinctly after the corrosion test. In this study, an ion implantation technique was applied to understand the corrosion mechanism of ceramics in the stead of the conventional corrosion test. Sodium ions were implanted in ceramics (100keV, 1.910ions/cm) and then heat treatment was performed at either 923K or 823K for 36ks in argon atmosphere. After that, products on the surface were analyzed using SEM and TEM observation and X-ray diffraction. Consequently, a kind of the corrosion product was not identified exactly, but the presence of corrosion products was confirmed on the surface. It caused by the amount of corrosion products was only a few. In future, it is necessary to carry systematically out the implantation and heat treatment under various conditions. Therefore, it seems that the beneficial information will be obtained to understand the corrosion mechanism of ceramics.