Effect of Nanostructured Surface on the Corrosion Behavior of RAFM Steels

Abstract

This study investigated the effect of a preformed nanostructured surface on the corrosion behavior of 9Cr2WVTa reduced activation ferritic/martensitic (RAFM) steel and 9Cr+AlSi steel (9Cr2WVTa with the 0.12 wt.% Al and 0.68 wt.% Si addition) at 700 °C in air and at 550 °C in liquid lead–bismuth eutectic (LBE) alloys. The nanostructured surface layer was fabricated by surface mechanical rolling treatment (SMRT). The results showed that the SMRT 9Cr+AlSi sample has a lower oxidation rate than the SMRT 9Cr2WVTa steel at 700 °C in air, due to the faster diffusion rates of Al, Cr and Si in the nanostructure and a higher diffusion driving force increased by Cr. The SMRT 9Cr+AlSi sample at 550 °C in oxygen-saturated LBE alloy also had a higher oxidation rate, due to the formation of Al and Si oxides in the internal oxide layer.