CORROSION OF 10CrNi45Al ALLOY IN AN OXIDIZING GAS ATMOSPHERE

One of the basic technological operations of the currently developed pyrochemical technology for reprocessing spent nitride nuclear fuel from fast neutron reactors (SNF RBN) is high-temperature treatment (HTT) in a gas environment. The aim of the work was to study the effect of oxygen-containing gas environments: a dry mixture of Ar-20 vol. % O and a mixture of Ar-20 vol. % O, with 60% humidity for the degradation of 10CrNi45Al alloy, a candidate material for the manufacture of the HTT apparatus. Corrosion tests lasting up to 1000 hours were carried out at 500C. It was established by the X-ray diffraction method that the main corrosion products formed on the surface of samples kept in a dry gas atmosphere are AlO, FeO and NiFeO. The presence of moisture in the gas environment contributes to the formation of NiO and NiСrO. In a dry gas mixture, an outer layer is observed on the surface of the sample, which is individual fragments of corrosion products: oxide compounds of iron, chromium, nickel. The surface of the material is covered with a continuous film with a thickness of 2 to 5 μm based on aluminum oxide. For samples tested in a wet gas mixture, a violation of the continuity of the internal protective layer was revealed. The outer loosened layer consists of iron oxides, under which a layer with a predominant content of oxygen-containing chromium compounds was revealed.