A metal–metal bonding process using metallic copper nanoparticles produced by reduction of copper oxide nanoparticles

• Published in: Journal of materials research and technology Vol. 3; no. 2; pp. 114 - 121
• Main Authors: Kobayashi, Yoshio, Abe, Yuki, Maeda, Takafumi, Yasuda, Yusuke, Morita, Toshiaki
• Format: Journal Article
• Language: English
• Published: Elsevier Editora Ltda 01.04.2014; Elsevier
• Subjects: Copper oxide; Metallic Cu; Metal–metal bonding; Nanoparticle; Metallic Cu; Metal–metal bonding; Copper oxide; Nanoparticle
• ISSN: 2238-7854
• DOI: 10.1016/j.jmrt.2013.12.003

Metal–metal bonding was performed using metallic Cu nanoparticles fabricated from CuO nanoparticles. Colloid solutions of CuO nanoparticles were prepared by the reaction of Cu(NO3)2 and NaOH in aqueous solution at reaction temperatures (TCuOs) of 20, 40, 60 and 80°C. CuO single crystallites with a size of ca. 10nm were produced, and they formed leaf-like aggregates. The longitudinal and lateral sizes of the aggregates decreased from 522 to 84nm and from 406 to 23nm, respectively, with an increase in TCuO. Colloid solutions of metallic Cu nanoparticles were prepared by reducing the CuO nanoparticles with hydrazine in the presence of cetyltrimethylammonium bromide. The size of the metallic Cu nanoparticles decreased from 92 to 73nm with increasing TCuO. Metallic copper discs were bonded with the metallic Cu nanoparticles by annealing at 400°C and 1.2MPa for 5min in H2 gas. The shear strength required to separate the bonded discs increased with increasing TCuO. A maximum shear strength of 39.2MPa was recorded for a TCuO of 80°C.