Nanoscale insights into the corrosion of EUROFER by lithium ceramics

In the advanced helium-cooled pebble bed (HCPB) blanket concept for future fusion reactors, reduced activation ferritic-martensitic steels are in direct contact with Li-based ceramics. This work provides a detailed nanoscale insight into the corrosion of EUROFER by Li ceramics based on analytical electron microscopy (AEM) analyses. AEM revealed a bilayer corrosion zone. In the outer zone structurally disordered LiFeO2 and ferrite were observed, whereas in the inner zone complex spinel-type oxides were found. Moreover, it was found that in EUROFER M23C6 precipitates are dissolved, but not the MX-type transition metal nitrides. Finally, suggestions to minimize the corrosion issue are provided.

Automated summary

This study provides a detailed nanoscale insight into the corrosion of EUROFER steel by Li-based ceramics using analytical electron microscopy (AEM) analyses. A bilayer corrosion zone was observed, with structurally disordered LiFeO2 and ferrite in the outer zone, and complex spinel-type oxides in the inner zone. Additionally, it was found that M23C6 precipitates in EUROFER steel were dissolved, while MX-type transition metal nitrides were not. Suggestions to minimize the corrosion issue were also provided.