The effect of Nb addition on the corrosion behavior of U-6Zr alloys within an aerated, demineralized water (DW) environment (pH 5.61) and its correlation of this addition with the mechanical and microstructural properties of the alloys were investigated. The U-6Zr-xNb alloys (x=1, 4, and 7 wt.%) were synthesized by arc-melting U, Zr, and Nb. Additionally, the samples were mounted and polished, after which they were subjected to electrochemical corrosion analysis using a potentiostat. This evaluation was conducted in a DW medium (pH 5.6), representing an aerated atmosphere, at room temperature (27°C) and a potentiodynamic scan rate of 1 mV/cm2. The results demonstrate that Nb addition to the U-6Zr alloy, which yielded a U-6Zr-xNb (x=1.4 and 7 wt.%) alloy, influenced the corrosion behavior in media, exhibiting a slightly acidic pH (5.61). Nb additions of up to 4 wt.% caused a continuous increase in the open-circuit potential, corrosion-current density, and corrosion rate (CR); however, these values decreased with the continuous increase in Nb concentrations to 7 wt.%. Furthermore, microstructural analysis via scanning electron microscopy and energy-dispersive X-ray spectroscopy revealed that the corrosion products across almost all U-6Zr-xNb test samples (x=0, 1, 4, and 7 wt.%) were primarily stable uranium dioxide, which formed a protective layer, followed by oxynitride and zirconium(IV) oxide. Overall, the findings indicated that the varying Nb contents (1, 4, and 7 wt.%) dictated the CR, mechanical properties, and microstructure of the alloys. Ultimately, this study demonstrates the synthesis of U-6Zr-xNb alloys (x=0, 1, 4, and 7 wt.%) with enhanced performance characteristics. © 2025, Universitas Indonesia. All rights reserved.