Mechanical properties of carbon nanotubes Mechanical properties of carbon nanotubes The mechanical properties of carbon nanotubes reveal them as one of the strongest materials in nature. Carbon nanotubes (CNTs) are long hollow cylinders of graphene. Although graphene sheets have 2D symmetry, carbon nanotubes by geometry have different properties in axial and radial directions. It has been shown that CNTs are very strong in the axial direction. Young's modulus on the order of and tensile strength of were obtained. Carbon nanotubes are the strongest and stiffest materials yet discovered in terms of tensile strength and elastic modulus respectively. This strength results from the covalent sp bonds
Diamond-like carbon various ways at the nanoscale level of structure, DLC coatings can be made that at the same time are amorphous, flexible, and yet purely sp bonded "diamond". The hardest, strongest, and slickest is such a mixture, known as tetrahedral amorphous carbon (ta-C). For example a coating of only 2 μm thickness of "ta-C" increases the resistance of common (e.g., type 304) stainless steel against abrasive wear, changing its lifetime in such service from one week to 85 years. Such "ta-C" can be considered to be the "pure" form of DLC, since it consists only of sp bonded carbon atoms. Fillers