Internal oxidation process in diluted Fe–Cr alloys: a transmission Mössbauer spectroscopy study

R Idczak

doi:10.1007/s00339-016-0544-3

Abstract

The room-temperature study of Fe0.97Cr0.03 and Fe0.94Cr0.06 alloys was performed using the transmission Mossbauer spectroscopy (TMS). The TMS measurements allow to determine changes in chemical composition and content of iron oxides in the bulk of the studied samples during exposure to air at 570, 870 and 1070 K. The results indicate that the chemical composition of samples changes significantly, and it is strongly dependent on temperature at which the studied samples are exposed to air. The iron internal oxidation kinetics as well as the activation energies for the oxidation of iron atoms in studied alloys were calculated.

Highlights

Today, the nuclear energy sector is looking for new structural materials which could be able to keep their design parameters for a long time during the exposure to factors such as corrosion, high temperature and high-energy neutron bombardment
One of the most interesting and promising types of structural materials which could be used in those innovative nuclear facilities is high-chromium ferritic/martensitic steels [1]
For samples exposed to air at 570 K for time shorter than 100 h, the transmission Mossbauer spectroscopy (TMS) spectra analysis reveal existence of components which could be assigned only to single-phase Fe–Cr alloy with bcc structure [3, 4]

Summary

Introduction

The nuclear energy sector is looking for new structural materials which could be able to keep their design parameters for a long time during the exposure to factors such as corrosion, high temperature and high-energy neutron bombardment. These conditions will exist in new types of advanced fission reactors (generation IV) and fusion reactors. One of the most interesting and promising types of structural materials which could be used in those innovative nuclear facilities is high-chromium ferritic/martensitic steels [1]. Upon ageing the Fe–Cr alloys with high chromium content often undergo transformation to either a high-temperature r phase or separation into Fe-rich (a) and Cr-rich (a’)

Objectives

Results

Conclusion