Effects of Infiltration Temperature, Time, and Gas Flow Rate on Material Properties of Carbon Infiltration Carbon Nanotubes

• Main Author: Sypherd, Shane Dirk
• Format: Others
• Published: BYU ScholarsArchive 2019
• Subjects: CI-CNT; carbon nanotubes; material properties; 3-point bend test; Engineering
• Online Access: https://scholarsarchive.byu.edu/etd/7733; https://scholarsarchive.byu.edu/cgi/viewcontent.cgi?article=8733&context=etd

This work characterizes the material properties of carbon infiltrated carbon nanotube (CI- CNT) structures. The impacts of temperature, time, and hydrogen flow rates on the material prop- erties of modulus of elasticity and strength are examined and compared. Carbon infiltration levels are assessed through the use of SEM images to determine which parameters give the highest level of infiltration. Through the use of SEM, carbon capping is observed on samples infiltrated for longer times at 900 and 950◦ C, suggesting that the samples are not being infiltrated during the entire desired infiltration period at these temperatures. The highest material properties of modulus and strength were reached when infiltrating the carbon nanotube forests for 150 mins at 850◦ C with hydrogen flowing at 311 sccm (0.0115 m/s). With these parameters, a modulus of 20.4 GPa and strength of 289.8 MPa were attained. The poorest results were seen when the samples were infiltrated at 800◦ C, and is therefore not recommended as an infiltration temperature if high mod- ulus and strength are desired. Density is correlated to strength and modulus and it is seen that there is a strong correlation between higher strength and modulus with higher density.