Presenter: Michelle Arias
Authors: Michelle Arias, Lucy Bowden, Brian Jensen, Anton Bowden
Faculty Advisor: Brian Jensen
Institution: Brigham Young University
Carbon-infiltrated carbon nanotubes (CICNT) are cylindrical molecules of carbon atoms with specific applications in medical implants. Different substrates require different CICNT growth processes. This study developed a growth method for CICNT on Ti6Al4V, a titanium alloy commonly used as a medical implant material due to its strong mechanical properties and biocompatibility. However, due to the presence of vanadium in the alloy, it is difficult to use it as a substrate for CICNT growth. To solve this problem, this study used an indirect growth method. This involved an initial barrier layer of alumina, followed by a catalyst layer of iron. There are several methods of depositing the barrier layer, and this study investigated the differences between electron-beam physical vapor deposition (PVD) involving evaporation deposition, and atomic layer deposition (ALD), a method of thin-film deposition that allows precise control of layer thickness. Three samples were included in each of five groups: PVD with 60 nm, 100 nm, and 200 nm of alumina and ALD with 30 nm and 50 nm. All other iron deposition, growth, and infiltration parameters were held constant. Once all samples were created, they were imaged using a scanning electron microscope. These images showed that the more error-prone PVD samples displayed patchier growths in the two lower thicknesses of the barrier layer. However, the more evenly arranged ALD layers as well as the 200 nm PVD layer showed excellent growth; the ALD 50 nm and PVD 200 nm samples had denser nanotube growth than the ALD 30 nm samples. These results illustrate the fact that Ti6Al4V can be used as a substrate for CICNT if a thick enough and even enough barrier layer is used. Since Ti6Al4V is an approved medical implant material, this experiment paves the way for future testing of CICNTs as a potential implant coating material.