Fabrication of copper-based calibration samples for glow discharge optical emission spectroscopy using powder metallurgy

This study demonstrates a processing route for producing copper matrix composite calibration standards with defined oxygen and boron contents for Glow Discharge Optical Emission Spectroscopy (GDOES). The influence of low-energy ball milling (LEBM) and high-energy ball milling (HEBM) on powder homogeneity, contamination, and the resulting microstructure was systematically evaluated. While LEBM preserved the particle morphology with minimal contamination, it did not provide sufficient dispersive efficiency, resulting in ceramic clustering at higher ceramic contents. In contrast, HEBM produced finely fragmented powders with improved mixing efficiency, although milling in air in the presence of a process control agent (PCA) caused significant contamination from oxidation and metallic abrasion. Milling under an inert atmosphere using Si₃N₄ media markedly reduced contamination. All samples achieved relative densities above 95 %. The produced materials showed good agreement between target and measured boron contents, confirming their suitability as boron reference materials for GDOES. Deviations in oxygen content were attributed to oxidation during milling and powder handling. Overall, the results highlight that optimized milling conditions and controlled oxygen exposure enable the fabrication of homogeneous copper-based calibration standards suitable for use as reference materials. • Copper-based calibration samples with defined oxygen and boron contents were produced using FAST/SPS. • Milling atmosphere and media were identified as key factors controlling contamination. • LEBM preserved morphology but lacked uniform ceramic dispersion. • Optimized milling and sintering conditions enabled dense Cu matrix composites suitable as reference materials.