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. The current work describes the behavior of the ferritic-martensitic steel T91 in a Heavy Liquid Metal environment. Specimens were pre-stressed up to yield strength and subsequently exposed to lead-bismuth eutectic (LBE) in static conditions for 2000 hours. The aim was to identify the susceptibility to crack initiation in the selected experimental conditions. In a reference position of the sample the examination of the metal-LBE interface was carried out by means of SEM equipped with EDX. On the interface, the formation of oxide scales was observed without trace of crack initiation. The oxide was characterized by a two layers structure. From the sample, a TEM lamella was produced by FIB and subsequently the lamella was analyzed in HRTEM. The individual oxide layers were identified and characterized by SAED, EELS and EDS techniques. For a visualization of the interface between matrix and oxide STEM-HAADF and EFTEM techniques were used.