Microstructural and morphological changes during ball milling of Copper-Silver-Graphite flake mixtures

Abstract

The present study reports the microstructural and morphological changes during high energy ball milling of Cu with Ag and Graphite flakes. XRD patterns of ball milled Cu-Ag showed a reduction in the intensity of Ag peaks (1 1 1) and an increase in the lattice parameter of Cu. With an increase in milling time, the formation of metastable Cu-Ag solid solution was observed. Lattice parameter values for 40 h milled Cu (3.6169 Å) and Cu-GF composites (3.6166 Å) indicated that C does not dissolve in Cu. The lattice parameter of Cu in milled Cu-Ag-graphite flake was lower compared to milled Cu-Ag mixture indicating that graphite flakes inhibit solid solution formation. Raman spectra revealed that graphite flakes were converted into multilayer graphene after 10 h of milling. The crystallite size of Cu in the milled powders decreased with increase in milling time and reached a value of ∼25 nm after 35 h of milling. The lattice strain also increased with milling time. The D10, D50 and D90 size reduced appreciably after 5 h of milling.