High-temperature oxidation of Zr-1Nb zirconium alloy with protective Cr/Mo coating

The oxidation and interdiffusion behavior of Cr- and Cr/Mo-coated Zr-1Nb zirconium alloy were investigated. A single-layer Cr (8 um) and multilayer Cr (8 mu m)/Mo (3 mu m) coatings were deposited by magnetron sputtering. The coated Zr-1Nb alloy samples were oxidized in air at 1100 degrees C for 15-60 min. Both coating types had a protective scale during high-temperature (HT) oxidation. The use of Mo sublayer resulted in preventing Cr-Zr interdiffusion under high temperature. Scanning electron microscopy, optical microscopy, X-ray diffraction before and after HT oxidation and in situ X-ray diffraction up to 1250 degrees C were used to identify interdiffusion behavior of the system of Cr/Mo/Zr. Some aspects of applying of Cr/Mo coatings for Zr nuclear fuel claddings are discussed.