Microbeam Analysis of a Commercial Advanced Gas Cooled Reactor Material

The role of silicon as a corrosion inhibitant was investigated by determining the concentration profiles of silicon and the other associated elements in the Commercial Advanced Gas Cooled Reactor (CAGR) material. The microbeam scanning method was employed. Three different alloys namely Fe-9Cr, Fe-9Cr -0.3%Si and Fe-9Cr -0.6%Si were studied by this technique. This, together with the microbeam analysis established the presence of silicon at the metal-oxide interface either alone as silica or coupled with the local chromium to form a chromium-silicon rich barrier layer which influenced the overall oxidation kinetics.