| WU Jinlong,LUAN Baifeng,ZHOU Hongling,YANG Xiaoling,HUANG Weijiu,SUN Chao.Research Progress Regarding Interfacial Element Diffusion Behavior of Chromium Coating on Zirconium Alloy Cladding[J],53(10):16-27 |
| Research Progress Regarding Interfacial Element Diffusion Behavior of Chromium Coating on Zirconium Alloy Cladding |
| Received:March 01, 2023 Revised:January 26, 2024 |
| View Full Text View/Add Comment Download reader |
| DOI：10.16490/j.cnki.issn.1001-3660.2024.10.002 |
| KeyWord:fuel cladding Cr coating interface element diffusion barrier layer |
| Author | Institution |
| WU Jinlong |
College of Materials Science and Engineering, Chongqing University, Chongqing , China |
| LUAN Baifeng |
College of Materials Science and Engineering, Chongqing University, Chongqing , China |
| ZHOU Hongling |
College of Materials Science and Engineering, Chongqing University, Chongqing , China |
| YANG Xiaoling |
College of Materials Science and Engineering, Chongqing University, Chongqing , China |
| HUANG Weijiu |
Institute of New Materials Technology, Chongqing University of Arts and Sciences, Chongqing , China |
| SUN Chao |
Science and Technology on Reactor Fuel and Materials Laboratory, Nuclear Power Institute of China, Chengdu , China |
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| Abstract: |
| With the development of nuclear reactors toward high fuel consumption and longer service life, higher requirements are placed on the safety and reliability of cladding materials. In order to address the nuclear fuel design defects exposed during the Fukushima nuclear accident, the research on accident tolerant fuel (ATF) has been carried out. Among several ATF cladding concepts, surface coating is the most promising strategy for engineering applications in the short term. Due to its excellent high-temperature oxidation resistance, corrosion resistance, and good compatibility with the substrate, Cr coating is considered to be the most promising accident resistant coating cladding material. The research results on element diffusion behavior at the Cr coating/substrate Zr interface in recent years were reviewed, focusing on the interface structure and evolution rules of Cr coatings in different states, including deposition, annealing, irradiation, oxidation and other states. The diffusion and distribution of Cr and the growth kinetic model of the intermetallic compound Zr-Cr-(Fe) layer were concluded, and the adverse effects of interfacial diffusion on the structural properties of the coating were summarized. ZrCr2 or Zr(Cr,Fe)2 interlayer is formed at the interface through Cr-Zr diffusion reaction. The growth of the intermediate layer is related to the manufacturing technology and roughly follows the diffusion-controlled parabolic law. The cold spray process removes the initial oxide film from the substrate and allows for faster growth compared to magnetron sputtering. Strong interdiffusion of elements at the interface can adversely affect the performance and microstructure of the coating, thus reducing its service life. The formation of the brittle interlayer at the interface accelerates the consumption of the protective Cr element and trends to become a path for crack propagation. The diffusion of Zr along Cr grain boundaries creates fast diffusion pathways for oxygen and promotes coating failure. The difference in Cr and Zr diffusion fluxes at the interface will cause vacancies to accumulate on one side, forming Kirkendall effect holes. The principles of barrier selection and existing and potential metallic or ceramic barrier materials are introduced, and the advantages and disadvantages of both types of barrier layers are analyzed. The metal barrier layer can inhibit the diffusion of Cr into the substrate and delay the Cr-Zr eutectic reaction, but the neutron economy needs to be considered. Although the ceramic barrier layer has excellent barrier performance, it is prone to microcracking due to the difference in mechanical properties and thermal expansion coefficient with zirconium alloy. Its crack resistance needs to be considered. At present, some results have been achieved in the study of the interface between coated Cr and substrate Zr, but there are still many scientific problems to be solved. For example, the research conditions of the interface remain at a single stress and a single oxidation. However, under the actual multi-factor coupling conditions of high temperature, stress and irradiation, the impact of diffusion on the interface bonding force and irradiation stability is still unclear. Most current interface research starts from an experimental perspective, fitting the tested macroscopic properties to obtain certain rules, but there is a lack of in-depth research on the internal structure of the coating. Using a multi-scale research method that combines experimental measurements with molecular dynamics simulations to reveal the mechanism of interface diffusion behavior is an important research direction in the future. |
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