| Nanotechnology means technology at the nanometer scale that is measured in billionth of a meter. Nanotechnology is a powerful tool for precise positioning of atoms and molecules. It allows construction of a wide range of artifacts where components may be measured in nanometres. Categories of Nanomaterials Nanomaterials may be classified into the following categories: • Nanoparticles • Nanofibres and Nanotubes • Nanofilms • Nanoblocks • Nanocrystalline alloys • Nanocomposites • Nanocrystalline solids Nanoparticles Submicron or ultra micron size particles available as high performance magnetic recording materials, magnetic fluid materials, randiant resistant materials, packaging materials and solar battery material. Nanofibres and Nanotubes Nanometer size long linear material, microconductors, microfibres, optical materials, nanotubes of PTFE, PET, PEEK (10 nm dia). Nanofilms Films used as gas catalyst materials. Nanoblocks Nanometer crystalline grain materials made by high precision forming nanoparticles or controlled crystallization. Nanocrystalline Alloys Alloys that have a majority of grain diameters in the typical range from 1 to 50 nm. Nanocomposites Composite materials which utilize nanoscale reinforcements instead of conventional particulates or fibres. Example: SiCp(Al) nanocomposite. Nanocrystalline Solids They are polycrystals the size of which is 1-10 nm so that 50% or more of the solid consists of inherent interface between crystals of different orientation. Clusters formed by homogeneous nucleation and grow by coalescence and incorporation of atoms. They display properties different from both the smaller atoms or molecules and the larger bulk materials. Nanocrystalline materials have been synthesized by several techniques such as inert gas condensating, electrodeposition, sputtering and mechanical attrition. |