Synthesis of metallic copper nanoparticles using copper oxide nanoparticles as precursor and their metal-metal bonding properties

摘要

This work proposes a method for preparing metallic Cu nanoparticles using CuO nanoparticles as a precursor, and performs metal-metal bonding by using the metallic Cu nanoparticles. Colloid solution of CuO nanoparticles with a longitudinal particle size of 13.0±3.0, a lateral particle size of 8.4±2.2 and a crystal size of 7.8 nm was prepared with salt base reaction using Cu(NO_3)_2 aqueous solution and NaOH aqueous solution. Preparation of the metallic Cu particle colloid solution was performed in water using the CuO nanoparticles, hydrazine and cetyltrimethylam-monium bromide, which resulted in production of the metallic Cu nanoparticles with a particle size of 50.6 nm and a crystal size of 30.5 nm. Metallic copper discs could be bonded using the metallic Cu nanoparticles under annealing at 400℃ and pressurising at 1.2 MPa for 5 min in H_2 gas. A shear strength required for separating the bonded discs was recorded as high as 39.6 MPa.