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

Abstract

Composite silver–copper (II) oxide powders were synthesized from mixtures of soluble precursors (aqueous silver and copper nitrates). The powder-making process employed was spray pyrolysis which has emerged as a promising technique (especially for the production of metal and alloy powders) because of its suitability for the production of high-purity, phase-pure, submicron-sized particles with molecular level of compositional homogeneity. Composite powders of silver and copper (II) oxide containing 60–95 vol.% silver were synthesized by spray pyrolysis of mixtures of aqueous silver and copper nitrates at 1000°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 external particle morphology, as seen by SEM, varied significantly with the powder composition. Surface smoothness and particle sphericity increased dramatically with increasing silver content, whereas the internal morphologies, as observed by TEM, were similar for all compositions. Thick film pastes of the Ag–CuO powders were used to print serpentine patterns which were fired and their resistivities measured. It was found that a Ag–CuO composite powder with 20 vol.% of CuO had resistivity comparable to pure Ag powder.