The development of accident-tolerant materials is of great significance for preventing the zirconium-water reactions and improving the inherent safety of nuclear reactors. In this study, ZrC/Ni multilayers with average layer thicknesses of 5, 10, 20, 50, and 100 nm were designed and successfully fabricated by magnetron sputtering. The characterization results of GIXRD, SEM, AFM, TEM, etc., show that the series of films are mainly composed of alternately deposited Ni crystalline layers and ZrC amorphous layers, and the interface is clear. The films were irradiated with 50 keV He+ with a fluence of 1.0 × 1017 ions/cm2 at room temperature, and the films with different layer thicknesses kept the original phase composition. It was found that an amorphous transition layer with a thickness of about 30 nm appeared between the amorphous and crystalline interface of the 100 nm film by TEM characterization. The analysis shows that this layer is formed by the mixing of Ni and Zr elements induced by irradiation, which is not conducive to He+ migration and produces large-sized helium bubbles. The appearance of the transition layer improves the irradiation stability of the amorphous/crystalline composite film, thus providing a theoretical basis for the application of this type of material in fuel cladding.
Keywords: accident-tolerant materials; amorphous ZrC; nanocrystalline Ni; resistance to He+ irradiation.