Study on the Preparation and Properties of Copper Nanoparticles and their Nanofluids

Nanoscale copper particles were synthesized by chemical reduction with polyvinyl pyrrolidone as dispersant, ascorbic acid as reduction agent, copper sulfate pentahydrate and ammonia as reagent. X-ray diffraction (XRD) analysis revealed that as-prepared copper nanoparticle was well crystallized without other impurities. Transmission electron microscopy (TEM) displayed that nanoscale coppers had homogenous distribution and the particle size was about 30~50 nm. Uniform and stable Cu-nanofluids were prepared by general stirring, high speed shear stirring and ultrasonic, with water/ethylene glycol as base fluid and as-synthesized copper nanoparticles as additives. The thermal conductivity of Cu-nanofluid was measured by a short-hot wire method. The results showed that the thermal conductivity of Cu-nanofluid was increased 8~9% compared to base fluid and the temperature had little effect on the enhancement of the thermal conductivity.