Preparation Of Diamond-like Carbon/Carbon Nanotubes Composite And Its Impact Resistance Research

Carbon nanotubes(CNTs)have attracted great attention in applications such as impact resistance and energy dissipation due to their unique structure and exceptional mechanical properties.Compared with traditional impact resistance materials,macroscopic assembly of CNTs(e.g.CNT arrays)have the advantages such as light weight,large specific volume dissipated energy and so on.However,CNT arrays still have their own problems as the impact energy dissipation materials.When the CNT arrays are subjected to impact,the physical interactions between the tubes are not strong enough to transfer the impact loading laterally(i.e.intertube transfer).Therefore,the stress concentrations occurred to the impacted area.This may lead to the structural damage of the impacted area and the incomplete use of the whole CNT arrays,thus limiting the specific volume dissipated energy of CNT arrays.In view of the above problems,we designed the diamond like carbon(DLC)/CNT arrays composite structure by depositing a layer of DLC films on the surface of CNT arrays.The hybrid structure was supposed to transfer of impact loading throughout the CNT arrays and then promote the specific volume dissipated energy of the CNT arrays.The main research contents are summarized as follows:(1)CNT arrays with uniform tube size and high purity(99.9%)were prepared by water-assisted chemical vapor deposition(CVD).By tailoring the catalyst system,we successfully tuned CNT arrays with the heights ranged from 0.3 to 1.4 mm and densities ranged from 10 to 50 mg/cm3.(2)The DLC/CNT composites were successfully synthesized by depositing a layer of DLC films(2 ?m)on the surface of CNT arrays through the ion implantation and deposition method.Scanning electron microscope(SEM)was applied to observe the surface morphology of DLC films and Raman spectroscopy was applied to explore the structural evolution from the DLC films and the CNT arrays.The results indicated the excellent adhesion between DLC films and CNT arrays.(3)The drop-ball impact tester was successfully set up.The measurement stability and impact speed ranged(1.44-3.00 m/s)of the tester were carefully tuned.The impact mechanical response of the CNT arrays and DLC/CNT arrays were both tested.The impact response of samples with the heights from 0.3 to 1.4 mm and densities from 10 to 50 mg/cm3 were plotted under the different impact speeds(1.44-3.00 m/s).The dependence of specific volume dissipated energy on structural properties of CNT arrays were investigated.(4)The influence of DLC films on the deformation evolution of CNT arrays during impact were also analyzed through the microscopic characterization of the CNT arrays before and after the impact test.The effect of the hybrid structure design on the specific dissipated energy of CNT arrays was examined.