Nature of diffraction fringes originating in the core of core–shell nanoparticle Cu/SiO2 and formation mechanism of the structures

Highlights: • The formation mechanism of core-shell nanoparticles Cu/SiO2 was studied. • The main part of oxygen in the nanoparticle is fixed with silicon. • Diffraction fringes in the nanoparticle are caused by the redistribution of silicon. • The emergence of fringes in the core is connected to extraction of metastable phases. This article is devoted to the analysis of the reasons for the occurrence of diffraction fringes in the cores of the core–shell nanoparticles Cu/SiO₂. Moiré and diffraction fringes are observed while studying the nanoparticle cores under a transmission electron microscope. The formation of diffraction fringes is closely connected to the mechanism of nanoparticle formation under study and appears to be its consequence, letting us develop a hypothesis of metastable phase formation in nanoparticle cores. In our opinion, the emergence of diffraction fringes in cores of copper is connected to clasterisation in solid solution oversaturated with silicon α-Cu with the diffused interphase state.