Development of analytical method for microstructure observation of oxide film on stainless steel

Development and research about analytical method for the study of oxide film on austenitic stainless steel had been conducted from the point of view for basic study of IASCC (Irradiation Assisted Stress Corrosion Cracking). Nickel plating and copper plating had been compared as the oxide film protection while the fabrication for cross sectional observation. And thin film specimens for microstructural observation were fabricated using FIB (Focused Ion Beam) technique. Microstructure of oxide film on stainless steel had been observed with FE-TEM (Field Emission gun - Transmission Electron Microscope), and the chemical composition was analyzed with EDS (Energy dispersed X-ray Spectrometer). The oxide film had been formed in high pressure (8 MPa) and high temperature (288degC) water, contains saturated oxygen. The thickness of oxide film was about 1 μm as maximum. Micro grains of Fe oxide with 100 nm in diameter were formed in the oxide film. On the boundary with alloy, there was about 10 nm thickness of passive film formed with Cr oxide. (author)