SEM image of a FIB-milled cross-section of a CNT spun yarn.
October 2011
The use of carbon nanotubes (CNTs) is increasing across a broad range of industries due to their strength and rigidity which is about 1000 times the strength of steel. However the breaking strength of spun CNTs is generally less than 1% than their theoretical value. MCN is collaborating with CSIRO to increase their potential usability.
Through collaborating on this project they have been able to delicately cross-section the yarns using the FEI Helios NanoLab 600 Dual-Beam Focused Ion Beam-Scanning Electron Microscope (FIB-SEM) at MCN and successfully characterise the internal structure of CNT yarns to reveal the effects of various yarn treatments.
Improving CNT yarn strength is one of the most challenging and critical issues for CNT technology. In addition, CNT yarns are also extremely difficult to cut without severe deformation of the yarn structures.
An example of the cross-section obtained by the FIB-SEM technique is shown above. To date, the researchers have developed a fabrication method that produces CNT yarns with a tensile strength of roughly 2.5 GPa, and the information obtained via the FIB-SEM cross- sectioning technique will enable them to further improve the fabrication methodology to produce yarns with even higher tensile strength.
