CHARACTERISATION OF OXIDES BY ADVANCED TECHNIQUES

Abstract

For the safe development of GenIV nuclear reactors, it is necessary to study the compatibility of structural materials with new coolants. Current work describes the behavior of ferritic-martensitic steel T91 in a Heavy Liquid Metal environment. Specimens were pre-stressed up to yield strength and subsequently exposed to the lead-bismuth eutectic (LBE) under static conditions for 2000 hours. The goal was to identify the susceptibility to crack initiation under selected experimental conditions. The examination of metal-LBE interface was done in a reference position of the sample using the SEM equipped with EDX. Formation of oxide scales observed on the interface had no signs of crack initiation. The oxide was characterized by a two-layer structure. A TEM lamella was created from the sample by a FIB in-situ lift-out technique and it was subsequently analyzed in HRTEM. Individual oxide layers were identified and characterized by SAED, EELS and EDS techniques. Finally, STEM-HAADF and EFTEM techniques were used to visualize the matrix-oxide interface.