A novel synchrotron technique for studying diffusion in solids
Bragg coherent diffraction imaging (BCDI) offers insights for nanoparticle synthesis
Measuring diffusion in solids
BCDI of gold-iron nanoparticles
The team measured the diffraction pattern of individual gold nanocrystals as a function of temperature and time, before and after iron deposition. They used phase retrieval algorithms to obtain real space reconstructions of the nanocrystals, observing alloying of iron with gold at sample temperatures of 300-500°C and dealloying of iron from gold at 600°C. They found that the volume of the alloyed region in the nanocrystals increased with iron dosage. Their results suggested that the samples reached equilibrium relatively quickly after iron deposition, and the resulting phase distribution within the gold nanocrystals after the iron depositions suggests a contraction due to diffusion of iron.