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In the fields of the nuclear industry and special high-end materials, tantalum (Ta), thanks to its extremely high melting point, excellent corrosion resistance, and mechanical properties at high temperatures, serves as an irreplaceable key material for applications such as plutonium production, nuclear material processing, and use in high-temperature molten salts under extreme conditions. It is a crucial foundation for ensuring the safe, stable, and long-term operation of nuclear facilities. However, under the most severe practical conditions—a molten salt environment + a chlorine/oxygen mixture atmosphere + high temperatures—chlorine reacts violently with tantalum to form volatile tantalum chlorides, leading to rapid corrosion and degradation of tantalum components as well as premature failure. This not only significantly increases production costs but also raises the risk of radiation exposure for operators, thus representing a key technical bottleneck that hinders the broader use of tantalum in nuclear applications. The core objective of this project is to address the issue of the insufficient resistance of traditional tantalum materials to chlorine corrosion. It focuses on the research and development as well as application of a new generation of tantalum surface alloy diffusion technology, in order to create a metallurgically bonded protective layer that significantly enhances the stability and service life of tantalum in highly corrosive environments involving chlorine and molten salts. This approach provides a revolutionary protection solution for the fields of plutonium production and special nuclear materials. 2 Technical pain points: Traditional solutions can no longer meet the requirements. Surface treatment methods such as conventional carburizing provide only limited improvement in tantalum’s resistance to chlorine corrosion, and it still fails rapidly in highly oxidative chlorinated molten salts. There is an urgent need for a new generation of surface modification technology that features strong adhesion, high-temperature resistance, and resistance to chlorine corrosion, in order to achieve true adaptation to operating conditions. 3 Core Technical Approaches: Next-generation Tantalum Surface Alloy Diffusion Technology. This project avoids broad-based screening and focuses specifically on next-generation tantalum surface alloy diffusion technology, while also incorporating control systems to highlight its advantages: • Primary focus: Next-generation tantalum surface alloy diffusion technology (to create an alloy protective layer with metallurgical bonding and controllable composition gradients) • Control systems: A few traditional surface modification processes, conventional coatings, and traditional tantalum alloys (used only for comparative verification). The key pretreatment process involves using a specialized Nitradd cleaning solution at 150°C to precisely remove carbon and oxygen contamination from the surface of the tantalum samples; quality is strictly controlled using EDS spectroscopy: the sample weight loss is greater than 30 mg, and the surface oxygen content is less than 1 wt%, thereby laying the foundation for the creation of high-quality alloy diffusion layers. Figure 1: Criteria for determining cleaning effectiveness. The correlation curve between the oxygen content measured by EDS and the weight loss of the samples after cleaning defines the acceptable threshold for the pretreatment using the new generation of tantalum surface alloy diffusion technology. Figure 2: Comparison of microstructure and elemental distribution before and after cleaning. The SEM morphology and EDS mapping clearly show that before cleaning: the tantalum surface contained numerous dark defect regions rich in carbon and oxygen, with impurity accumulation ； After cleaning: Surface carbon-oxygen impurities are significantly removed, and the uniformity is greatly improved, meeting perfectly the surface requirements for alloy diffusion. 4 Key Achievements: Major breakthroughs in the new generation of tantalum surface alloy diffusion technology. 1. Preparation of high-quality diffusion layers: Utilizing the new generation of tantalum surface alloy diffusion technology, it was possible to create protective layers on the surface of industrially pure tantalum that feature metallurgical bonding, no cracks, and controllable composition gradients, thereby addressing the problems of easy coating detachment and the inability of traditional modified layers to withstand high temperatures. 2. The sample system was fully established: 80 tantalum samples were subjected to standardized cleaning, of which 60 were used specifically for the development of new generation alloy diffusion technologies; meanwhile, 20 untreated samples were retained as blank controls to form a complete performance verification matrix. 3. Microstructural verification meets requirements: The specimens subjected to recovery and diffusion treatment were analyzed using SEM and EDS to characterize their cross-sectional morphology and elemental diffusion patterns, confirming that the alloying elements have effectively penetrated into the tantalum matrix to form a dense gradient protective structure, thereby providing a solid foundation for subsequent corrosion performance tests. 5 Technical Value: Tantalum’s “robust armor” for enhancing safety in the nuclear industry. Breakthroughs in new-generation tantalum surface alloy diffusion technologies bring three key advantages: • Strong adhesion: metallurgical bonding rather than physical coating, providing resistance to high-temperature impacts and making it difficult for the coating to peel off ； • Strong resistance to chlorine corrosion: significantly inhibits the erosion of tantalum by chlorine and molten salts, extending the lifespan of components ； • High adaptability: Designed specifically for nuclear-grade tantalum components, it is suitable for use in key applications such as plutonium production, nuclear waste treatment, and molten salt processes. As a key material capable of withstanding the extreme conditions in the nuclear industry, tantalum is equipped with \"long-lasting armor\" thanks to the latest generation of surface alloy diffusion technologies, which ensure the safety of nuclear facilities at the material level, help reduce costs and improve efficiency, and support stable operation. Statement: This article was first published on the official WeChat account [Tantalum and Niobium New Technology Services and Applications]