ZrO2/Cr Multilayer Coating for the Protection of E110 Zirconium Alloy from High Temperatures

Cr coatings with a multilayer barrier composed of alternating ZrO2 and Cr layers with an individual thickness of each layer of 50 and 250 nm are deposited onto substrates made from E110 zirconium alloy using magnetron sputtering. The protective properties of the ZrO2/Cr multilayer coating on E110 zirconium alloy are studied under high-temperature oxidation in air at a temperature of 1100 degrees C for 10, 20, 30 and 40 min. A lower rate of change in the weight gain of the samples with ZrO2/Cr coatings is found in comparison with samples coated by chromium during long-term oxidation tests. Diffraction measurements of the samples are carried out under linear heating (50 degrees & Scy;/min) in the range of temperatures 25-1250 degrees & Scy; and subsequent isothermal treatment for 20 min in a vacuum chamber with a residual pressure of 10(-3) Pa using in situ synchrotron X-ray diffraction. It is found that the mutual diffusion of Cr-Zr at the interface between the protective coating with the multilayer barrier composed of alternating ZrO2 and Cr layers and zirconium alloy can be slowed down. This results in the retention of a high content of the alpha-Cr phase in the coating and, as a result, in an increase in the duration of the protective state of the E110 alloy under high-temperature oxidation in air.