Abstract Uranium as an important energy material plays a significant role within the field of material sciences and nuclear industrial applications. However, metallic uranium is chemically active in ambient environment and is easily oxidized and corroded, leading to not only deterioration of its properties and failure of performance as working components but also nuclear pollution of the environment. Therefore, the development of corrosion protection systems for metallic uranium is an issue of prime importance. In view of the nitridation technology in Ti and Fe-based alloys, the successful application to improve the surface wear hardness and corrosion resistance, several nitridation methods have been developed for the surface modification of metallic uranium. Many studies have shown that the surface nitridation of metallic uranium can efficiently improve its corrosion resistance. The surface oxidation layer thickness is as thin as several nanometers even if placed 4 years in the atmosphere. At the present, nitridation of uranium surface is considered as the most promising surface modification way to protect uranium from corrosion. To design and fabricate nitride layers on uranium surface with reliable long-term protective effects, however, one needs deep understanding on the relationships among the physical and chemical properties of the nitride layers, the composition and structure of the layers, and the dependence on the techniques and the processing parameters. One also needs deep understanding on the corrosion behavior of the prepared nitride layers in the environment, and the related corrosion mechanism. In this review, we bring to the readers the achievements and recent advances on the uranium nitridation in the world, including the processing techniques and the related studies on the formation mechanism of the nitride layers, and the understanding on the property-processing-corrosion performance relationship of the layers, aiming at the development of high-performance resistance layers for metallic uranium by the surface nitridation technique. In the review (1) the surface nitridation techniques developed recently, the relationship between the preparation parameters and the composition as well as the structure of the surface layer are summarized; (2) the fundamental physical properties of the uranium nitrides are summarized, depicted and discussed; (3) the influence of the nitrides structure and composition and of the environment on resistance to corrosion as well as the formation mechanism of corroded products in oxidizing environments are depicted and discussed; (4) the potential application of uranium nitrides in other application field such as the application of thermal-electrical conversion is also discussed. Finally, the prospective on the investigations of nitride layers is suggested.

中文翻译：

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铀表面的氮化物层

摘要 铀作为一种重要的能源材料，在材料科学和核工业应用领域发挥着重要作用。然而，金属铀在周围环境中具有化学活性，容易被氧化和腐蚀，不仅导致其作为工作部件的性能劣化和性能失效，而且还会对环境造成核污染。因此，金属铀腐蚀保护系统的开发是一个最重要的问题。针对钛基和铁基合金的氮化技术，在提高表面耐磨硬度和耐腐蚀性能方面的成功应用，已经开发了几种用于金属铀表面改性的氮化方法。许多研究表明，金属铀的表面氮化可以有效提高其耐腐蚀性能。即使在大气中放置4年，其表面氧化层厚度也薄至数纳米。目前，铀表面氮化被认为是保护铀免受腐蚀的最有前途的表面改性方法。然而，为了在铀表面设计和制造具有可靠长期保护作用的氮化物层，需要深入了解氮化物层的物理和化学性质、层的组成和结构之间的关系，以及对铀表面的依赖。工艺和加工参数。还需要深入了解制备的氮化物层在环境中的腐蚀行为，以及相关的腐蚀机理。在这篇综述中，我们为读者带来了世界上铀氮化方面的成就和最新进展，包括处理技术和氮化层形成机制的相关研究，以及对性能-处理-腐蚀性能的理解。层之间的关系，旨在通过表面氮化技术开发金属铀的高性能电阻层。综述（1）近年来发展起来的表面氮化技术，总结了制备参数与表面层组成及结构之间的关系；(2) 对氮化铀的基本物理性质进行了总结、描绘和讨论；(3) 描述和讨论了氮化物的结构和组成以及环境对耐蚀性的影响以及氧化环境下腐蚀产物的形成机制；(4) 还讨论了氮化铀在其他应用领域的潜在应用，如热电转换应用。最后，对氮化物层的研究提出了展望。