Rare‐Earth Tantalates RE 3 TaO 7 for Extreme Nuclear Environment Applications

The development of Generation IV nuclear reactors, such as the supercritical water‐cooled reactor (SCWR) and the lead‐bismuth‐cooled fast reactor (LFR), is significantly hindered by the degradation of structural materials under extreme operational conditions. Currently, widely investigated coating materials, including yttria‐stabilized zirconia (YSZ), SiC, and RE 2 Zr 2 O 7 , fail to satisfy the multiple requirements imposed by extreme nuclear environments. Consequently, the development of ceramics for nuclear protective coatings is imperative. Rare‐earth tantalates RE 3 TaO 7 possess many desirable properties, including excellent chemical stability, high‐temperature stability, high thermal expansion coefficients (TECs = 9.0–12.0 × 10 −6 K −1 ), relatively low thermal conductivities (1.0–2.1 W·m −1 ·K −1 ) desirable for coolant‐facing protective coatings on reactor structural components, and outstanding tolerance to irradiation‐induced amorphization, thereby rendering them promising candidates for structural component protection in extreme nuclear applications. This review comprehensively describes the failure mechanisms of structural alloys in coolant environments and defines the essential property requirements for nuclear protective coatings. We summarize the current research status of conventional coatings, including YSZ, SiC, and RE 2 Zr 2 O 7 , and point out the advantages of the thermophysical properties of RE 3 TaO 7 in diverse environments. This work suggests that RE 3 TaO 7 ceramics are promising candidates for further development as nuclear protective coatings and outlines their future research directions.