CoNiCuCrS alloy nanoparticles: synthesis and atomically resolved T/STEM studies

In this paper, we reported the synthesis and characterization of CoNiCuCrS nanoparticle alloys using scanning transmission electron microscopy (STEM) techniques. The nanoparticles form hexagonal platelets with an average size of 34.5 nm. Atomic resolution STEM imaging reveals an ordered FCC crystal structure with a lattice parameter of 0.93 nm, consistent with a (CuCo)₆Ni₃Cr₁S_13.333 intermetallic phase. The paper provided direct experimental evidence of the strain distribution at the atomic scale using advanced STEM techniques. The findings are consistent with previous studies, confirming the presence of small but significant strains in high entropy alloys (HEAs). By studying nanoparticles, we achieved atomic-resolution imaging and characterization, which is challenging with bulk HEA samples. The work revealed that defects like stacking faults and partial dislocations, stabilized by the presence of sulphur in our sample, play an important role in the mechanical properties of HEAs. This research demonstrated that nanoparticles can be used as a model for studying bulk properties of HEAs, providing insights into local strain effects and crystal growth dynamics.