The ability of silicide coating to delay the catastrophic oxidation of vanadium under severe conditions

N. Chaia (1) , S. Mathieu (1) , F. Rouillard (2) , Michel Vilasi (1)

1 IJL - Institut Jean Lamour
2 LECNA - Laboratoire d'Etude de la Corrosion Non Aqueuse

V-4Cr-4Ti vanadium alloy is a potential cladding material for sodium-cooled fast-neutron reactors (SFRs). However, its affinity for oxygen and the subsequent embrittlement that oxygen induces causes a need for an oxygen diffusion barrier, which can be obtained by manufacturing a multi-layered silicide coating. The present work aims to evaluate the effects of thermal cycling (using a cyclic oxidation device) and tensile and compressive stresses (using the three-point flexure test) on the coated alloy system. Tests were performed in air up to 1100 degrees C, which is 200 degrees C higher than the accidental temperature for SFR applications. The results showed that the VSi2 coating was able to protect the vanadium substrate from oxidation for more than 400 1-h cycles between 1100 degrees C and room temperature. The severe bending applied to the coated alloy at 950 degrees C using a load of 75 MPa did not lead to specimen breakage. It can be suggested that the VSi2 coating has mechanical properties compatible with the V-4Cr-4Ti alloy for SFR applications.

Domaines: Chimie inorganique

N. Chaia, S. Mathieu, F. Rouillard, Michel Vilasi. The ability of silicide coating to delay the catastrophic oxidation of vanadium under severe conditions. Journal of Nuclear Materials, 2015, 457, pp.124-129. ⟨10.1016/j.jnucmat.2014.11.015⟩. ⟨hal-01295119⟩