Diffusion-induced recrystallization in nickel/palladium multilayers

Kasprzak M., Baither D., Schmitz G.

Abstract

In size-mismatched thin film interdiffusion couples diffusion-induced recrystallization (DIR) occurs rather than conventional Fickianatomic transport. Grains formed in this process have characteristic composition levels that are so far not understood. In this work, DIRis studied in sputter-deposited Ni/Pd films. By pre-alloying one side of the diffusion couple, the mismatch, and thus the driving force, arevaried. After heat treatment, transmission electron microscopy, energy-dispersive X-ray spectroscopy and X-ray diffractometry demonstraterecrystallization. Characteristic concentration levels are derived from X-ray diffraction data. Remarkably, the concentration insidenewly formed grains shifts coherently to the concentration inside the parent layers. We demonstrate that the observed concentration levelsare in agreement with a recently published thermomechanical model.