A team of researchers from Florida State University’s High-Performance Materials Institute is developing a new design for a heat shield that better protect composite materials on satellites, rockets and jet aircraft.
The team are using carbon nanotubes, which are linked hexagons of carbon atoms in the shape of a cylinder, to build the heat shields. Sheets of those nanotubes are also known as “buckypaper,” a material with incredible abilities to conduct heat and electricity that has been a focus of study at HPMI. By soaking the buckypaper in a resin made of a compound called phenol, the researchers were able to create a lightweight, flexible material that is also durable enough to potentially protect the body of a rocket or jet from the intense heat it faces while flying.
Existing heat shields are often very thick compared to the base they protect, said Ayou Hao, a research faculty member at HPMI. This design lets engineers build a very thin shield, like a sort of skin that protects the aircraft and helps support its structure.
After building heat shields of varying thicknesses, the researchers put them through a series of tests including applying a flame to see how they prevented heat from reaching the carbon fibre layer they were meant to protect. After that, the researchers bent the samples to see how strong they remained.
They found the samples with sheets of buckypaper were better than control samples at dispersing heat and keeping it from reaching the base layer. They also stayed strong and flexible compared to control samples made without protective layers of nanotubes.
That flexibility is a helpful quality. The nanotubes are less vulnerable to cracking at high temperatures compared to ceramics, a typical heat shield material. They’re also lightweight, which is helpful for engineers who want to reduce the weight of anything on an aircraft that doesn’t help the way it flies.
The project received second place among peer-reviewed posters at the 2019 National Space and Missile Materials Symposium and received a third place at the Society for the Advancement of Material and Process Engineering 2019 University Research Symposium.