The growth of carbon nanotube multilayers on ceramic μ-particles by catalytic chemical vapour deposition

Aligned multi-walled carbon nanotube (CNT) multi-layers have been synthesized on micro-spherical alumina particles and on micro-platelet silicon carbide particles. Liquid injection catalytic chemical vapour deposition is used in this work through sequential injections of aerosols containing both carbon feedstocks (xylene and acetylene) and catalyst precursor (ferrocene). The two substrate materials have been chosen due to their large surface areas but different shapes and compositions. The CNT stack formation process coupled with real-time in situ mass spectrometry and gas phase chromatography has been tailored to investigate the effects of several factors such as growth temperature, hydrogen flow rate, reaction time, carbon source(s), catalyst concentration, injection speed and substrate's nature and morphology on the CNT growth. The simultaneous feeding of catalysts and carbon sources combined with the use of non-flat micro-sized substrates consists of a promising approach for large scale production. The as-prepared hybrids can be then used as reinforcements for multi-functional composite applications.