Oxidation and Nitriding Tubes of Zr-1%Nb Zirconium Alloy

The work presents results of saturation of Zr-1% Nb tubes after processing in oxygen- and nitrogen- containing gas environments. The distribution of micro-hardness in the thickness of the tube and the thickness of the hardened layers, the weight gain was determined. It is found that the oxidation of the Zr-1%Nb alloy (Т = 650°С, РО2=2.6·10-1 Pа, τ = 3…20 h) makes a greater weight gain than nitriding (Т = 650°С, τ = 5…20 h). The state of the surface of the inside and outside of Zr-1%Nb tubes for fuel cladding depending of the processings time was shown. The differences in saturation of outside and inside of the tube was showed. In particular, the hardness of internal surface of the tube is smaller relative to the outside after oxidizing and nitriding was found. The results of study of the outer and inner surface of fuel cladding in contact with gaseous environment containing oxygen and nitrogen are interesting for investigators of reactor materials.