<p>The effects of welding time on the mass diffusivity and interfacial corrosion behavior of solid-state diffusion-welded joints fabricated using zirconium alloy (Zr702) and super duplex stainless steel (SDSS) having a Nickel alloy (NiA) interlayer were investigated in this study. The diffusion welding was employed at 875 °C temperature under varying welding times of 30, 45, 60, 75, and 90 min under a pressure of 4 MPa in a vacuum atmosphere. The critical characterization of interface microstructure revealed that the interface between SDSS and NiA exhibited a planar morphology. On the contrary, distinct layer-wise reaction products, such as Ni₅Zr, Ni₁₀Zr₇, NiZr, and NiZr_2, were identified at the NiA and Zr702 interface. A molecular dynamics simulation approach was applied to identify the diffusion mechanisms at the FeNi and NiZr interfaces. The highest corrosion rate was observed in the joint produced with 90 min of welding time as per the electrochemical assessment, indicating micro-galvanic corrosion due to intermetallic compounds at the joint interface.</p>