Effect of stratification in a liquid state in the Nb-ZrO2 system on lithium penetration into alloys at 673 K

Durable investigations of the behaviour of alloys of the Nb-ZrO2 cross section in melted lithium are carri.ed out with the aim of clarifying the reasons for the incompletc cessation of the corrosion process, irrespective of the fact that the Zr:O=1:2 ratio is observed in the alloys. It is shown that in the alloys of the Nb-Zr-O system placed in the Nb-ZrO2 cross section in composition first ZrO2 precipitations are found starting with 0.12 mol% ZrO2. Three phases are present in the alloys, they are α-Nb, (Zr, Nb)O2 and NbO. Alloy stratification in the liquid state starting with 0.12 mol% ZrO2 to the α-solid zirconium and oxygen solution in niobium and ZrO2 with a partial substitution of zirconium atoms with niobium (Zr, Nb)O2 with a monoclinic structure is found for the first time. Stratification in the liquid state is evidently limited by the Nb-ZrO2 cross section in this system. Lithium penetration into alloys of the Nb-ZrO2 series in the process of long-term ageing at 673 K takes place due to zirconium dioxide reduction by lithium at this temperature