Surfactant-stabilized copper paticles for low-temperature sintering: Paste preparation using a milling with small zirconia beads : Effect of pre-treatment with the disperse medium

Copper paste is considered as a promising candidate for printed electronics in replacement for silver paste. This is owing to copper which has anti-electromigration property, lower cost, and similar conductivity and compared with silver. We synthesize a copper nanoparticle (NP) paste that can be sintered at low temperature for high conductivity. The copper NP paste composes of 50 wt% copper NPs and dipropylene glycol (DPG) as the disperse medium. The effect of DPG coating and various conditions of milling with small beads on improving the dispersity of copper NPs has been investigated. The optimum conditions for milling are at 1000 and 2000 rpm for 30 min. This results in a volume resistivity of 6.62 x 10(-6) Omega.cm after sintering the copper NP paste at 200 degrees C. (C) 2020 The Society of Powder Technology Japan. Published by Elsevier B.V. and The Society of Powder Technology Japan. All rights reserved

The role of surface oxides and stabilising carboxylic acids of copper nanoparticles during low-temperature sintering

This article provides a detailed discussion of 1-hexanoic-acid-stabilised copper nanoparticles with an average diameter of similar to 80 nm prepared from cupric oxide micro-powders for low-temperature sintering applications. The obtained fine particles were dispersed in dipropylene glycol using a bead mill to obtain a stable paste containing 50 wt% copper. Sintering experiments at temperatures in the range of 120-250 degrees C were performed under a nitrogen or 3%H-2-N-2 gas flow. The lowest resistivity, approximately three times that of bulk copper, was obtained at 250 degrees C. These particles exhibited good conductivity upon sintering under nitrogen only. 1-Hexanoic acid contributed to the acceleration of sintering by removing the Cu64O oxide layer of the particles and activating the surface. The dispersed copper paste and the copper layer after sintering were observed using SEM

A liquid metal catalyst for the conversion of ethanol into graphitic carbon layers under an ultrasonic cavitation field

Eutectic gallium indium (EGaIn) has drawn considerable research interest in potential liquid catalysis. Herein, we report that EGaIn liquid metal acts as a catalyst for the growth of a graphitic carbon layer from ethanol under ultrasonication. High-speed imaging demonstrated the formation of ultrasonic cavitation bubbles at the liquid metal/ethanol interface, which facilitated the pyrolysis of ethanol into graphitic carbon on the liquid metal surface