Amorphous sputter coating of a multi-component Zr–Ti–Ni–Cu alloy as a filler for brazing Zircaloy-4

Abstract

Amorphous sputter coatings of a Be-free multi-component Zr–Ti–Ni–Cu alloy were applied as a novel brazing filler metal for brazing Zircaloy-4. The homogeneous and amorphous-structured layers were uniformly coated by sputtering the crystalline Zr47.6Ti19.9Ni17.4Cu15.1 target. By preserving the near equivalent target composition, the coating showed an excellent compositional uniformity in spatial distribution, as well as almost the same melting characteristics as that of the parent target. By applying the amorphous sputter coatings, the highly reliable joints were obtained with the formation of predominantly grown α-Zr grains due to a complete isothermal solidification, exhibiting strengths comparable to that of Zircaloy-4. The present investigation showed that a Be-free and Zr-base multi-component amorphous sputter coating can offer great potential for brazing and manufacturing a Zr alloy nuclear fuel bundle system.