Deep-Sintered Copper Tracks for Thermal Oxidation Resistance Using Large Pulsed Electron Beam

Abstract

Thermal oxidation resistance is an important property in printed electronics for sustaining electrical conductivity for long time and/or under harsh environments such as high temperature. This study reports the fabrication of copper nanoparticles (CuNPs)-based conductive tracks using large pulsed electron beam (LPEB) by irradiation on CuNPs to be sintered. With an acceleration voltage of 11 kV, the LPEB irradiation induced deep-sintering of CuNPs so that the sintered CuNPs exhibited bulk-like electrical conductivity. Consequently, the sintered Cu tracks maintained high electrical conductivity at 220 °C without using any thermal oxidation protection additive, such as silver, carbon nanotube, and graphene. In contrast, the films irradiated with an acceleration voltage of 8 kV and irradiated by intense pulsed light (IPL) showed fast oxidation characteristics and a corresponding reduction of electrical conductivities under high temperatures owing to a thin sintered layer. The performance of highly thermal oxidation-resistant Cu films sintered by LPEB irradiations was demonstrated through the device performance of a Joule heater.

High‐Temperature Hybridized Copper–Boron Nitride Materials from Additive Manufacturing

“…The metal conductor utilization for high-temperature applications has proved difficult from failure caused typically by its oxidation. [2,[6][7][8][9][10][11] There is a need for reliable conductors with high electrical conductivity as well as high oxidation resistance for the development of next generation of electronics suitable for operating under elevated temperatures. This limits the material candidates for high-temperature electronics to a selected few metals like gold, [5,10,12,13] silver, [5,10,13,14] or platinum.…”

Ultrahigh Temperature Copper-Ceramic Flexible Hybrid Electronics

“…Copper, on the contrary, is highly abundant, has high conductivity, and relatively high melting point. [9][10][11]17,18 However, bulk copper is known to have a high susceptibility to oxidation in ambient conditions. 9,17,18 Additionally, printable FHEs typically utilize nanoscale materials, which exacerbates the problems with oxidation and corrosion, relative to its bulk counterparts.…”

“…[9][10][11]17,18 However, bulk copper is known to have a high susceptibility to oxidation in ambient conditions. 9,17,18 Additionally, printable FHEs typically utilize nanoscale materials, which exacerbates the problems with oxidation and corrosion, relative to its bulk counterparts. 10,11 To address these issues, tremendous efforts have been explored to improve the conductor through additives or alloying strategies.…”

“…Precious metals, such as gold, platinum, and silver, , show great promise due to their inherent physicochemical properties; however, the low abundance and high cost of these metals prove to be limiting factors, necessitating the need for other materials. Copper, on the contrary, is highly abundant, has high conductivity, and relatively high melting point. − ,, However, bulk copper is known to have a high susceptibility to oxidation in ambient conditions. ,, Additionally, printable FHEs typically utilize nanoscale materials, which exacerbates the problems with oxidation and corrosion, relative to its bulk counterparts. , To address these issues, tremendous efforts have been explored to improve the conductor through additives or alloying strategies. ,,,− To further improve the conductor from environmental effects, it could be shielded from reaching very high temperatures or preventing oxidation in the first place.…”

“…Here we explore new strategies toward greater oxidation and thermal stability of printed electronics comprised of copper-based conductors and flexible ceramic substrates. The first strategy is to optimize conductor composition, which revolves around reconstructing the copper on the atomic scale through alloying or the structural surface coating on an atomic level. , Copper–silver (CuAg) alloys typically provide corrosion resistance or higher thermal stability. The Cu/Ag (core/shell) structure, on the other hand, requires Ag to be coated on the surface, providing a passivating layer to protect the copper from oxidation and corrosion.…”