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The fretting corrosion behaviors of Cr-coated Zr‐1Nb alloy claddings with Zr-4 dimple and Inconel 718 spring in simulated PWR primary water were investigated. The results indicated that by increasing the fretting duration from 192 to 427 h, the maximum wear depth and volume of Cr coating with dimple increased by 15% and 3%, respectively. In the case of spring as a grinding material, however, the maximum wear depth and volume significantly increased by about 8 and 300 times, respectively. At 427 h, the Cr coating was worn through, and oxidation of the underlying Zr‐1Nb substrate formed a dual-layered oxide film. • Fretting corrosion of Cr-coated Zr‐1Nb tube in high temperature water was studied. • A third-body layer composed of debris was formed after fretting corrosion. • Abrasive and/or stripping wear dominated the fretting corrosion mechanism. • The damage caused by fretting corrosion with dimple is less than that with spring. [ABSTRACT FROM AUTHOR]

The isothermal oxidation behavior of magnetron-sputtered Cr-coated Zr-1Nb alloy cladding in 1000–1300 ℃ steam environment is studied. The phenomena at each temperature are summarized and the oxidation kinetics are discussed. Cr coating can maintain the oxidation resistance for more than 6 h at 1000 ℃ and 1100 ℃ under double-sided oxidation condition, while suffered degradation during long-duration oxidation at 1200 ℃ and 1300 ℃. After coating degradation, Zr substrate was oxidized prior to residual metallic Cr and the metallic Cr was not completely oxidized until the ZrO 2 layer beneath the coating had grown to a certain thickness. Mainly due to the redox reaction between Zr and Cr 2 O 3 and the preferential oxidation of Zr substrate, the thickness of Cr 2 O 3 film decreased after a certain oxidation duration. The Cr coating after degradation at 1200 ℃ can still hinder the oxidation of Zr substrate to a certain extent, while that at 1300 ℃ almost lost the protective effect. • Isothermal steam oxidation of Cr-coated Zr alloy was performed in temperature range of 1000–1300 ℃. • Oxidation kinetics of Cr-coated Zr alloy cladding was summarized. • Oxidation behavior of Zr substrate after coating degradation were discussed. [ABSTRACT FROM AUTHOR]