Carbon-infiltrated carbon nanotube (CICNT) surfaces are cylindrical sheets of carbon atoms with a honeycomb molecular structure. CICNT possess structural anti-biofilm activity against bacteria. Their ability to prevent the formation of these biofilms depends on specific parameters, including the average nanotube diameter. Nanotube growth occurs when carbon-rich gas flows over certain surfaces in a high temperature furnace.This study develops a growth method for CICNT diameter changes on Ti6Al4V, a titanium alloy commonly used as a medical implant material due to its strong biomechanical properties. For this experiment, we analyzed the effect of carbon infiltration times on average nanotube diameter. Ti6Al4V samples were cleaned and prepared for nanotube growth by the deposition of a barrier layer of alumina, followed by a catalyst layer of iron. The prepared samples were then placed in a furnace with hydrogen gas flowing. A nanotube growth step was performed at 750 degrees Celsius for 1 minute with ethylene and hydrogen gasses flowing. During this phase the nanotubes gain their height. Following the growth step, an infiltration step was performed at 900 degrees Celsius at times ranging from 2 to 16 minutes, with three samples in each group. During this phase the nanotubes grow in diameter. Once the CICNT samples were completed they were imaged in a scanning electron microscope (SEM) to determine the average diameter of each sample. These diameters were correlated with infiltration time, and it was found that there was a strong positive linear correlation between infiltration time and CICNT diameter, d = 18.8833t - 30.8409 where d represents the diameter in nanometers and t is the time in minutes. These results illustrate that the CICNT infiltration time can be fine-tuned to control nanotube diameter, which will allow us to better investigate the mechanism behind the way they affect bacterial biofilms.