Preparation Of Ultra - Fine Copper Powder By Electrolysis In Choline Chloride - Urea Eutectic Solvent

Ultrafine copper powder because of its excellent electrical conductivity, thermal conductivity, no magnetic conductivity, corrosion resistance, etc, and has many characteristics of the nanometer materials have been powder metallurgy, conductive coatings, the important raw material for shielding material production. Dendritic ultrafine copper powder because of its special appearance makes it compared to other morphology has better compactibility and sintering properties, better able to model a structure compact powder metallurgy products; In the lubrication material production, dendritic binding force greater than the ball between copper powder and flake copper powder.In this paper, Dendritic ultrafine copper powder was prepared in accordance with the molar ratio of 1:2 to choline chloride and urea mixture of eutectic type ionic liquids, as the electrolyte, elemental copper anode, pure titanium plate as cathode, oxalic (H2C2O4·2H2O) as additive, constant current electrolysis.This paper studies have shown that electrolysis system of the peak shape of infrared absorption peak before and after no change, shows no change as well as electrolytic system. The analysis of FT-IR has shown that the maximum absorption wavelength of Cu2+ and Cu+ in [1ChCl:2Urea]/H2C2O4·2H2O DES are 306 and 307nm. This system has excellent electrical conductivity that the efficiency of electrolysis can be improved enormous, and when the temperature rise from 30 ℃ to 50 ℃, the electrical conductivity from 400μS·cm-1 to 3200μS·cm-1.Single factor and response surface experiment study have shown that dendritic copper powder of particle size smaller than 15 μm were obtained when the process conditions were controlled on temperature 80℃, current density 8.60 mA·cm-2, and H2C2O4·2H2O 0.10 mol·L-1. The current efficiency of copper powders electrolysis was high as 95.6%, and the electricity consumption was 1746 (kW·h)·t-1. Copper powder can be made with good oxidation resistance that cleaned in order by Oxalic acid aqueous solution with 0.1 mol·L-1, aqueous solution of polyvinyl alcohol with 3g/L and anhydrous ethanol.The cyclic voltammograms has shown that the windows of [1ChCl:2Urea]/0.1 mol·L-1 H2C2O4·2H2O DES is 2.1V. During the electrolysis the oxalic can be decomposed and keeping release hydrogen, in favor of protect the copper powder that separate out from cathode avoid oxidized, and also can promote the pulverize of copper powder.