Microstructural Characterization of Ag-Based Composite Powders Prepared by Mechanical Milling

Ag-based composite powders have attracted significant attention due to their superior electrical conductivity, thermal conductivity, and antibacterial properties, which are closely related to their microstructural characteristics and elemental distribution. In this work, Ag-based composite powders were fabricated via a high-energy mechanical milling process, followed by microstructural characterization using scanning electron microscopy (SEM), backscattered electron (BSE) imaging, energy-dispersive X-ray spectroscopy (EDS), and fracture surface analysis. The SEM observations revealed Ag particles embedded within a composite matrix, with average particle sizes ranging from approximately 0.6 to 1.2 µm. The BSE images indicated a uniform distribution of the high atomic number element Ag in the matrix, while the EDS elemental mappings confirmed the coexistence of Ag, Al, and O phases. Fracture morphology analysis suggested a combination of brittle and ductile fracture features, corresponding to the heterogeneous particle–matrix interface. Based on literature data, the microstructural features observed are expected to enhance the electrical and thermal transport properties, while also introducing antibacterial effects due to Ag incorporation. This study highlights the importance of structural and compositional analysis in designing Ag-based functional materials.