Metal fiber materials, in particular, are frequently used in composites to impart electrical conductivity. The use of high aspect ratio metal fibers with random orientation in the composite matrix material allows for low fiber loading while achieving good electrical conductivity. Such low level loadings, however, impart little benefit to the tensile strength of the composite, which is almost unchanged relative the parent matrix material. While increasing the loading of metal fiber might improve tensile strength, it can negatively impact the overall weight of the composite material.
It would be beneficial to provide an agent that allows the electrical conductivity properties of metal fiber materials to be realized in a composite while also enhancing the metal fiber-matrix material interface and, ultimately, the tensile strength of the composite material. The present invention satisfies this need and provides related advantages as well.
In some aspects, embodiments disclosed herein relate to a continuous CNT infusion process that includes: (a) disposing a barrier coating and a carbon nanotube (CNT)-forming catalyst on a surface of a metal fiber material of spoolable dimensions; and (b) synthesizing carbon nanotubes on the metal fiber material, thereby forming a carbon nanotube-infused metal fiber material.
FIG. 3 shows an SEM image of about 1 micron long CNTs in a mat-like arrangement grown on stainless steel mesh, under high magnification.