Processing and characterization of CNT/Cu nanocomposites by powder technology

Abstract

Carbon nanotube/copper (CNT/Cu) nanocomposite powders with different volume fractions of multiwall CNTs (MWNTs) are prepared using e electroless Cu deposition method in alkaline citrate bath. The prepared CNT/Cu nanocomposite powders are investigated with HRSEM. The CNT/Cu nanocomposite powders have morphology of implanted CNTs in the copper particles of about 200 nm in size. An electroless deposited pure Cu powder is also prepared by the same method to compare the properties of pure copper samples and the prepared CNT/Cu nanocomposites. The prepared powders undergo XRD and elemental analysis to evaluate the fabricated CNT/Cu nanocomposites. The XRD patterns and elemental analysis inform that the deposited copper is composed of Cu powder and traces of some elements, e.g., sulfur and oxygen. The CNTs/Cu nanocomposite, as well as the pure copper powders, is sintered by spark plasma at 600 °C and compaction pressure of 20 MPa for one min under 10−3 torr vacuum condition. The microstructure of the sintered nanocomposites is investigated with SEM. The CNTs are homogenously distributed in the copper matrix in the case of CNT/Cu nanocomposites with CNT volume fraction up to 10 vol.% has a porosity of 3%, and the porosity increases by increasing CNT volume fraction due to the agglomeration of the CNTs in the copper matrix. The electrical resistivities of the prepared sintered copper and CNT/Cu nanocomposites are measured with four-probe method. The results show that the highest resistivity is 13.5 µΩ · cm for 40 vol.% CNT/Cu.