Enhanced erosion resistance and radiation stability of WC-WO3 nanocomposite films under 100 keV Kr+ ion irradiation.

Abstract

Plasma-facing components (PFCs) in fusion reactors are exposed to extreme radiation and thermal environments, leading to material degradation processes such as sputtering erosion and amorphization. This study investigates and compares the erosion behaviour of tungsten (W) in potential ceramic-based PFC materials, specifically tungsten carbide (WC) thin films and their nanocomposite counterpart, WC-WO₃, under 100 keV Kr⁺ ion irradiation. The films were irradiated at fluences of 1 × 10¹⁶, 3 × 10¹⁶, and 1 × 10¹⁷ ions/cm². Rutherford backscattering spectrometry was employed to evaluate W sputtering yields and compositional stability. The WC-WO₃ nanocomposite exhibited significantly reduced W erosion compared to pure WC films, attributed to the higher W binding energy and the existence of heterointerfaces within the nanocomposite matrix. SRIM simulations corroborated the experimental sputtering trends. Furthermore, preferential sputtering of lower-Z elements (C and O) was observed in both material systems. Glancing incidence X-ray diffraction analysis revealed post-irradiation grain growth in WC-WO₃ films, while scanning electron microscopy results show morphological changes, indicating dynamic microstructural evolution rather than amorphization under irradiation. These results highlight the potential of WC-WO₃ nanocomposites as erosion-resistant and structurally resilient candidates for future plasma-facing applications in fusion reactors.