Mechanical alloying of multi-walled carbon nanotubes reinforced aluminum composite powder

Carbon nanotubes (CNT) have emerged as a very promising reinforcement for ceramics, polymers and metals. Although the CNT reinforced composites show a significant improvement in mechanical, thermal and electrical properties, there are several critical challenges to the effective use of carbon nanotube reinforce composites such as agglomeration of CNT, poor distribution and weak bond between CNT and base matrix. In this paper, mechanical alloying (MA) was applied by the authors to disperse CNT in the aluminum matrix. Both stearic acid and ethanol were used as process control agents (PCA) to control the properties of particles. Scanning electron microscope (SEM), Raman spectroscope and particle size analyzer were employed to characterize the size, shape and morphology of the CNT–Al composite. The evolutions of CNT and CNT–Al mixture as well as the effect of PCA were studied. The present research indicates that mechanical alloying is an effective way to achieve homogenous distribution of CNT in the Al matrix. Ethanol as process control agent promotes the refinement of Al particles but also increases the damage of CNT during the ball milling process.