Preparation of Ultrafine Copper Powders with Controllable Size via Polyol Process with Sodium Hydroxide Addition

Abstract

A facile polyol process for producing copper powders with controllable size is described here. The copper powders have been readily synthesized by the reduction of copper (II) nitrate trihydrate with the solution of glycerol and sodium hydroxide. The X-ray diffraction, SEM and FESEM were used to characterize the obtained copper powders. The effect of the concentration of NaOH and the reaction temperature were investigated. The sizes and the complete reaction time of the copper powders were decreased at the condition of increasing the concentration of NaOH and the reaction temperature. For example, at the constant reaction temperature of 140°C, the sizes of the obtained powders of the molar ratio of NaOH:Cu(NO₃)₂ range from 2:1 to 5:1 were decreased from 1.40 to 0.10 µm as well as the complete reaction times which were reduced from 240 to 17 minutes, respectively. By controlling the process parameters the uniform nano-sized copper powders could be achieved at the optimal condition.