Charging of V-4Cr-4Ti by oxygen to create in situ insulator coating

Oxidizing of V-4Cr-4Ti in flowing Ar-O2 (PO2 = 1-5 × 10−2 Pa) at 973-1273 K has been investigated. The mechanism of interaction between V-alloy and gaseous medium was found to change around 1011 K. At higher temperatures, T > 1011, the interaction is controlled by oxygen absorption in the alloy. At T < 1011 K, oxygen diffusion is accompanied by fine Ti-O precipitation with high density, limiting the depth of oxygen penetration into the alloy. Based on comparative analysis of the results obtained and reference data, the formation of an inner oxidizing zone at low temperature has been modeled. In the context of the model, the availability of this structure to produce Er2O3 on the V-4Cr-4Ti surface in contact with the Li(Er) melt is considered.