Improving the Compressive Strength of Carbon Nanotube Turfs by Adding Iron Nanowires to the Nanotube Core

The cores of carbon nanotubes (CNTs) are partially filled by Fe nanowires during synthesis by chemical vapor deposition from an acetylene–ferrocene mixture. A Fe-filled CNT turf is produced with a height exceeding 100 μm and a Fe-filling ratio of 33%–48%. The diameters of the Fe nanowires inside the CNTs range from 10 to 20 nm. With the Fe-filling of the CNT core rising to 48.1%, the compressive modulus of the turf increases from 4.9 to 71.8 MPa and the hardness from 0.534 to 2.044 MPa.