| Pacific Rim Symposium on Surfaces, Coatings and Interfaces (PacSurf 2018) | |
| Thin Films | Tuesday Sessions |
| Session TF-TuP |
| Session: | Thin Films Poster Session I |
| Presenter: | Jung-Hwan Park, Korea Atomic Energy Research Institute |
| Authors: | J.H. Park, Korea Atomic Energy Research Institute Y.I. Jung, Korea Atomic Energy Research Institute D.J. Park, Korea Atomic Energy Research Institute H.G. Kim, Korea Atomic Energy Research Institute B.K. Choi, Korea Atomic Energy Research Institute Y.H. Lee, Korea Atomic Energy Research Institute J.H. Yang, Korea Atomic Energy Research Institute |
| Correspondent: | Click to Email |
After the Fukushima Daiichi nuclear accident, the major issue of nuclear researchers has been an improvement in the oxidation resistance under beyond-design accident conditions. Therefore, accident tolerant fuel (ATF) has been widely studied, which has high-temperature oxidation resistance. For the development of ATF claddings, several advanced cladding materials that have high-temperature oxidation resistance have been proposed, including advanced stainless steels, Mo alloys, and SiC/SiCf composites. However, they require changes in the engineering design of the reactor cores. An alternative approach to improving safety is to fabricate a cladding with a protective coating. A protective coating that has a high oxidation resistance also improves the corrosion performance during normal operation. Several coating materials have previously been suggested, including SiC, FeCrAl, TiN, TiAlN and Cr. Among the candidate materials for protective coating, Chromium coatings are well known for their high hardness, good corrosion, and wear resistance. In our previous work, Cr coating deposited on a zircaloy-4 cladding by cathodic arc ion plating was investigated to evaluate the corrosion protection of zircaloy-4 cladding in a high-temperature steam environment. Compared to pristine Zircaloy-4, Zircaloy-4 with a Cr layer exhibited superior oxidation resistance. However, an oxygen-stabilized alpha zirconium (α-Zr(O)) layer, which was formed through oxygen diffusion, was observed after a high-temperature steam oxidation test.
In this study, we tried to optimize the ion plating conditions to reduce the inward oxygen diffusion. Cr coatings were deposited on a Zircaloy-4 tube using arc ion plating at various substrate bias voltages. The effects of the substrate bias voltage on the corrosion behavior of arc ion plated Cr films has been investigated. We also investigated the relationships among the substrate bias voltage, physical properties, and corrosion resistance for Cr coated zircaloy-4. The internal stress was measured using an iso-inclination method with an x-ray diffractrometer at room temperature. A high-temperature steam oxidation test at 1473 K was executed.