Refractory materials, such as molybdenum and niobium, are potential candidates for cladding material due to their high melting temperatures and desirable mechanical properties at higher temperatures than those of zirconium alloys. However, refractory materials have low resistance to oxidation at elevated temperatures. Therefore, this study examined silicide or aluminide surface coatings as protection against rapid oxidation of refractory materials at elevated temperatures for a potential accident-tolerant fuel cladding. Silicide or aluminide layers were formed on refractory metal substrates by using the pack cementation method. The steam oxidation behavior of both coated and uncoated samples was compared by thermogravimetric analysis at 1200°C. The weight changes of the coated samples were greatly reduced than those of uncoated samples. Microstructural analyses demonstrated that the silicide and aluminide layers were oxidized to form a protective surface oxide that prevented rapid oxidation of the refractory substrate at elevated temperatures.

1. Introduction 
2. Materials and Methods 
    2.1. Refractory metals 
    2.2. Surface coating 
    2.3. Oxidation test 
    2.4. Microstructural analysis before and after oxidation 
3. Results 
    3.1. Microstructure 
    3.2. Thermogravimetric analysis 
    3.3. Sample morphology after oxidation test 
4. Conclusions 
Funding
Conflict of Interest  
Data Availability Statement 
Author Information and Contribution 
Acknowledgement
References

• Ho Jin Ryu(Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea) Corresponding author
• Je-Kyun Baek(Department of Nuclear and Quantum Engineering, Korea Advanced Institute of Science and Technology, Daejeon 34141, Republic of Korea)
• Hyun Gil Kim(Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea)
• JaeJoon Kim(Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea)
• Woojin Lim(Korea Atomic Energy Research Institute, Daejeon 34057, Republic of Korea)