锆合金包壳在微动磨蚀环境下的界面损伤行为

Fretting corrosion of zirconium (Zr) alloy fuel rod cladding with spacer grid will occur due to flow induced vibration in reactor. The corrosion accelerated wear between fuel rod cladding and spacer grid in high temperature water environment has not been considered in the existing research. The fretting corrosion behavior of Zr alloy cladding in different potential (–0.8 V, –0.4 V, 0 V, 0.4 V, and 0.8 V) is studied by fretting wear test equipment combined with electrochemical workstation. The SEM, EDS, XPS, EBSD, and 3D optical microscope are used to obtain the information of morphology and surface chemical composition. The friction oxidation behavior and fretting damage mechanism of Zr alloy under different applied potentials are studied. The results show that the corrosion current in the fretting process increases with the increase of potential, which accelerates the oxidation corrosion of Zr alloy in the wear process and aggravates the fretting damage. The obvious furrows and oxide particles accumulated on the surface of wear scar in different potential is observed. The main wear mechanism is abrasive wear and oxidation wear. The wear depth and wear rate of Zr alloy increase with the increase of potential, because the increase of potential would accelerate corrosion and improve the interaction between wear and corrosion, resulting in the wear rate increasing. The effect of potential on the wear morphology, wear volume, and interaction of wear and corrosion of Zr alloy is revealed. The wear mechanism of Zr alloy under different potential conditions is clarified, and this paper provides the theoretical support for the analysis and prediction of fretting corrosion behavior of Zr alloy in long-term operation condition.