Cailiao Baohu (Jun 2023)
Preliminary Study of Characteristics of Thermal Oxidation Film of Zirconium Alloy Cladding in Typical High Temperature Air
Abstract
The thickness and density of the zirconia ceramic layer formed on the surface of the zirconium alloy cladding are the main factors affecting its wear resistance. In this paper, the variation of thickness and density of zirconia ceramic layer with time during thermal oxidation of three different composition zirconium alloys, Zr-Sn, Zr-Nb, and Zr-Sn-Nb, in typical high temperature air at 560 ℃ and 600 ℃ was studied. The maximum thickness of the dense zirconia ceramic layer that could be formed by thermal oxidation of zirconium alloy cladding with different compositions in air during the experimental characterization time was explored. Results showed that the maximum thickness growth rate of zirconia ceramic layer in Zr-Nb zirconium alloy cladding at typical temperatures during the test period was the largest, that of Zr-Sn-Nb zirconium alloy cladding took second place, and that of Zr-Sn zirconium alloy cladding was the smallest. The thickness growth rate of zirconia ceramic layer in zirconium alloy cladding with the same composition at 600 ℃ was about twice that of 560 ℃. When the thicknesses of zirconia ceramic layer of Zr-Sn and Zr-Sn-Nb zirconium alloy cladding were 4~5 μm and 9~10 μm at 600 ℃, respectively, the obvious crack were observed, while the zirconia ceramic layer thickness of Zr-Nb zirconium alloy cladding reached 12 μm at 600 ℃, the density of this ceramic layer was good, and no obvious cracks were observed.
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