Generation and sintering characteristics of silver-copper (II) oxide composite powders made by spray pyrolysis

Composite silver-copper (II) oxide powders were synthesized from mixtures o f soluble precursors (aqueous silver and copper nitrates). The powder-makin g process employed was spray pyrolysis which has emerged as a promising tec hnique (especially for the production of metal and allay powders) because o f its suitability for the production of high-purity, phase-pure, submicron- sized particles with molecular level of compositional homogeneity. Composit e powders of silver and copper (II) oxide containing 60-95 vol.% silver wer e synthesized by spray pyrolysis of mixtures of aqueous silver and copper n itrates at 1000 degrees C. Air was used as the carrier gas. Novel particle morphologies were obtained. The powder particles were silver and copper (II ) oxide composites with the phases well dispersed in the particles. The ext ernal particle morphology, as seen by SEM, varied significantly with the po wder composition. Surface smoothness and particle sphericity increased dram atically with increasing silver content, whereas the internal morphologies, as observed by TEM, were similar for all compositions. Thick film pastes o f the Ag-CuO powders were used to print serpentine patterns which were fire d and their resistivities measured. It was found that a Ag-CuO composite po wder with 20 vol.% of CuO had resistivity comparable to pure Ag powder. (C) 2000 Elsevier Science S.A. All rights reserved.