Structural property comparison of Ca–Mg–Zn glasses to a colloidal proxy system

We compare various structural properties of the Ca–Mg–Zn ternary metallic glass system at compositions Ca60MgXZn40−X (where X = 25, 20, 15, 10) to a colloidal proxy system containing “Red”, “Green” and “Blue” particles at the corresponding compositions R60GXB40−X. The methacrylate-based polymer colloid particles have the same relative radius ratio as their atomic counterparts and surface electrostatic charges are employed to mimic atomic interactions. The structures of these colloidal suspensions are investigated through laser scanning confocal microscopy, with each particle species labeled with red, green and blue fluorescent dyes. We find qualitative agreement with number densities and many characteristics of the partial radial distribution functions and partial coordination numbers between the atomic and colloid systems. In general, coordination numbers agree within experimental error. Total coordination numbers for Red-centered clusters are found to be slightly higher than the corresponding Ca-centered clusters, while Green- and Blue-centered clusters have slightly fewer neighbors than Mg- and Zn-centered clusters. These and other differences are noted and possible explanations of these are offered, as well as ways that the proxy system might be improved to more accurately reproduce the structure of the metallic system.