CARBON NANOTUBES :
CNT is a tubular form of carbon with diameter as small as 1 nm. Length: few nm to microns. CNT is configurationally equivalent to a single or multiple two dimensional graphene sheet(s) rolled into a tube (single wall vs. multiwalled).
CNT exhibits extraordinary mechanical properties: Young’s modulus over 1 Tera Pascal, as stiff as diamond, and tensile strength ~ 200 GPa.
CNT can be metallic or semiconducting, depending on (m-n)/3 is an integer (metallic) or not (semiconductor).
CNT Properties :
The strongest and most flexible molecular material because of C-C covalent bonding and seamless hexagonal network architecture
• Strength to weight ratio 500 time > for Al, steel, titanium; one order of magnitude improvement over graphite/epoxy
• Maximum strain ~10% much higher than any material
• Thermal conductivity ~ 3000 W/mK in the axial direction with small values in the radial direction
• Very high current carrying capacity
• Excellentfieldemitter;highaspectratioandsmall tip radius of curvature are ideal for field emission
• Can be functionalized.
CNT Synthesis :
- CNT has been grown by laser ablation (pioneered at Rice) and carbon arc process (NEC, Japan) – early 90s.
- SWNT, high purity, purification methods
CVD is ideal for patterned growth (electronics, sensor applications) – Well known technique from microelectronics
- Hydrocarbon feedstock
- Growth needs catalyst
- Growth temperature 500-950° deg. C.
- Numerous parameters influence CNT growth
The above details shows that the potential of Nano materials in Aviation Sector. Using nanotechnology in aviation gives the Light Weight, High Strength, High Toughness, Corrosion Resistance, Easy Reparability & Reusability, Less Maintenance & Durability hence it becomes cheaper, safer and used for protecting the structures and surfaces of the aircraft from harsh environments than the conventional. This technology has some drawback also but due to above reason it can be ignored.
Nanotechnology is an enabling technology that will impact the aerospace sector through composites, advances in electronics, sensors, instrumentation, materials, manufacturing processes, etc.
• The field is interdisciplinary but everything starts with material science. Challenges include:
– Novel synthesis techniques
– Characterization of nanoscale properties – Large scale production of materials – Application development
• Opportunities and rewards are great and hence, there is a tremendous worldwide interest.