Advanced Materials: TechConnect Briefs 2015Advanced Materials TechConnect Briefs 2015

Nanoparticle Synthesis & Applications Chapter 5

Temperature Stability of AgCu Nanoparticles

J. Sopousek, O. Zobac, V. Vykoukal, J. Bursik, P. Roupcova, P. Broz, J. Pinkas, J. Vrestal
Masaryk University, Czech Republic

pp. 278 - 281

Keywords: silver, copper, KEMS, HTXRD, DSC, transformation

The Ag-Cu nanoparticles (NPs) were prepared from metallo-organic precursors by solvothermal synthesis. The CALPHAD approach was used for prediction of the Ag-Cu phase diagram in both macro and nano scales. The detailed experimental characterization was also done. The AgCu NP microstructure study was performed by various methods including high-resolution transmission electron microscopy (HRTEM) and X-ray diffraction. The prepared AgCu nanoparticles exhibited a metastable structure. The face centred cubic (FCC) crystal lattice where the silver atoms are randomly mixed with copper was confirmed by HRTEM and HTXRD methods. The temperature induced phase transformation of the metastable AgCu nanoparticles was observed experimentally by AgCu NP heating inside high temperature X-ray powder diffractometer (HTXRD) under synthetic air. The phase transformation of the FCC_A1 phase was detected and the changes were measured. The heating was conducted to different maximal temperatures up to 450 C. The start temperatures of the nanoparticle aggregation and sintering were evaluated. The melting point of the AgCu NPs was measured by differential scanning calorimetry (DSC). The study of the protective surface organic layer was performed by Knudsen effusion mass spectroscopy (KEMS).