Abstract

Copper/carbon fiber (Cu/CF) composites by electroless Cu deposition were studied on carbon fibers (CF) produced at three different heat treatment temperatures (HTT) of 1000, 1500, and 2000 °C. The HTT control led to different CF graphitization indexes that influenced their chemistry surfaces. As a consequence, the electrochemical and chemical pre-treatments of the CF played distinct role by forming different oxygen functional groups also influencing the Cu deposition. CF substrates as well as Cu/CF composites were analyzed by Raman spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction, and scanning electron microscopy. FTIR results revealed that both pre-treatments promoted CF surface modifications concerning the OH stretching vibrations for the three HTT studied. Nonetheless, the OH stretching vibration was more intense for all electrochemically pre-treated CFs. Moreover, the C-O and C=O stretching vibrations also appeared for the electrochemically pre-treated CF1000. Cu electroless deposition showed a strong dependence on the CF microstructure acquired after the HTT as well as on the pre-treatment step. The electrochemical pre-treatment was mandatory to obtain metallic Cu deposits on CF substrates. Regarding the nitrate electrochemical reduction, Cu/CF composites obtained from electrochemically treated CFs showed the nitrate reduction to nitrite followed by ammonia formation.

Keywords: Carbon fiber; Graphitization index; Copper deposition; Electroless process; Heat treatment temperature