Studies of atomic diffusion in Ni-Pt solid solution by x-ray photon correlation spectroscopy

TL;DR

This study uses atomic-scale x-ray photon correlation spectroscopy to investigate atomic diffusion in Ni-Pt alloys, revealing diffusion mechanisms, short-range order effects, and activation energies consistent with tracer studies.

Contribution

It demonstrates the application of aXPCS to Ni-Pt alloys, providing new insights into diffusion mechanisms and short-range order effects at atomic scales.

Findings

Activation energy of 2.93 eV for diffusion.

Diffusivities around 10^-23 m^2/s at 830 K.

Sensitivity of aXPCS to short-range order effects.

Abstract

Atomic scale x-ray photon correlation spectroscopy (aXPCS) was used to study atomic diffusion in the Ni97 Pt3 solid solution with both a single crystal and a polycrystalline sample. Different jump diffusion models are discussed using experimental results and Monte Carlo simulations. The sensitivity of aXPCS experiments to short-range order (in this case governed by a strong Pt-Pt repulsive force) is demonstrated. The activation energy of 2.93(10) eV as well as diffusivities in the range of 10-23 m2 s-1 at 830 K agree very well with the results of tracer diffusion studies at much higher temperatures.