Effect of W concentration on the thermal stability of Cu-carbon nanotube hybrids

Abstract

Carbon nanotube (CNT)-metal hybrids have been increasingly focused as a promising candidate for flexible circuit, but the metal agglomeration is their main failure mode under elevated temperature. In this study, we found the thermal stability of Cu-CNT hybrids can be significantly enhanced by W alloying. For CNT-Cu hybrids, the nano-grains suffered from serious agglomeration and growth after annealing at 473 K. And this phenomenon could be more significant by increasing annealing temperature. By adding W atoms with 4 at% into Cu matrix, the grain growth is weakened during annealing and the agglomeration is suppressed even at the temperature of 673 K. As the W content increases, the agglomeration is further suppressed at the higher temperature (873 K). The mechanism for the improved thermal stability was related to the stabilized grain boundaries by W atoms that were dissolved into Cu during deposition and further precipitated at higher W content or/and higher annealing temperatures.