HCM12A oxide layer investigation using scanning probe microscope

Kikuchi, Kenji*; Rivai, A. K.*; Saito, Shigeru   ; Bolind, A. M.*; Kogure, Akinori*

The oxide layer on the 12Cr steel, HCM12A, is investigated using a scanning probe microscope (SPM), which was formed in lead bismuth eutectic (LBE) at 450500C, during 5500 hrs. Hitherto oxide formation mechanisms were studied from viewpoints of the location of original base metal surface, the pass for oxygen travel and Fe diffusion to understand the stability of oxide layer. The new findings in this research are that surface potential measurement detected the boundary between (FeCr)O and FeO, which is not found at the topographic mode measurement. The spinel layer can be distinguished from the bulk area with lower surface potential profile, but near the boundary between the spinel and magnetite layers the surface potential profile seems to be continuous except for the narrow path corresponding to the boundary line. The band structure penetrating magnetite and spinel layer was found, which was not found at the topography.