In this study, we present a novel strategy for fabricating binary-array surface-enhanced Raman scattering (SERS) substrates composed of gold (Au) and silver (Ag) plasmonic hexagonal nanoplates (h-NPLs), functioning as a "nanoalloy" system. Using Au h-NPLs as scaffolds, we synthesized Ag h-NPLs of closely identical sizes and shapes, facilitating the construction of a mixed plasmonic system. The flat morphology of h-NPLs enables their face-to-face assembly into parallel "wire-like string" arrays, referred to as "columnar superpowders (SPs)", which expose nanogaps perpendicular to the incident light and maximize near-field focusing. We achieved anisotropic superstructures of Au-Ag core-shell h-NPLs through epitaxial Ag growth on Au surfaces, controlled by the interplay of halide ions and surface crystal energy differences. Free-standing columnar SPs were fabricated