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Nanophase Materials
Nanophase materials are materials that have grain sizes under 100 nanometres. They have different mechanical and optical properties compared to the large grained materials of the same chemical composition. Transparency and different transparent colours can be achieved with nanophase materials by varying the grain size. Nanophase materials *Nanophase metals usually are many times harder but more brittle than regular metals. ** nanophase copper is a superhard material ** nanophase aluminum ** nanophase iron is iron with a grain size in the nanometer range. Nanocrystalline iron has a tensile strength of around 6 GPA, twice that of the best maraging steels. *Nanophase ceramics usually are more ductile and less brittle than regular ceramics. Footnotes External links Creating Nanophase Materials ''Scientific American'' (subscription required) Nanophase Materials ''Michigan Tech'' ''Louisiana State University Louisiana State University (officially Louisiana State University an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanometre
330px, Different lengths as in respect to the molecular scale. The nanometre (international spelling as used by the International Bureau of Weights and Measures; SI symbol: nm) or nanometer (American and British English spelling differences#-re, -er, American spelling) is a units of measurement, unit of length in the International System of Units (SI), equal to one billionth (short scale) of a metre () and to 1000 picometres. One nanometre can be expressed in scientific notation as , and as metres. History The nanometre was formerly known as the millimicrometre – or, more commonly, the millimicron for short – since it is of a micron (micrometre), and was often denoted by the symbol mμ or (more rarely and confusingly, since it logically should refer to a ''millionth'' of a micron) as μμ. Etymology The name combines the SI prefix ''nano-'' (from the Ancient Greek , ', "dwarf") with the parent unit name ''metre'' (from Greek , ', "unit of measurement"). ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Optical Properties
The optical properties of a material define how it interacts with light. The optical properties of matter are studied in optical physics, a subfield of optics. The optical properties of matter include: *Refractive index *Dispersion *Transmittance and Transmission coefficient *Absorption *Scattering *Turbidity *Reflectance and Reflectivity (reflection coefficient) *Albedo *Perceived color *Fluorescence *Phosphorescence *Photoluminescence *Optical bistability * Dichroism *Birefringence *Optical activity *Photosensitivity A basic distinction is between isotropic materials, which exhibit the same properties regardless of the direction of the light, and anisotropic ones, which exhibit different properties when light passes through them in different directions. The optical properties of matter can lead to a variety of interesting optical phenomena. Properties of specific materials *Optical properties of water and ice *Optical properties of carbon nanotubes *Crystal optics See also *Rama ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chemical Composition
A chemical composition specifies the identity, arrangement, and ratio of the elements making up a compound. Chemical formulas can be used to describe the relative amounts of elements present in a compound. For example, the chemical formula for water is H2O: this means that each molecule of water is constituted by 2 atoms of hydrogen (H) and 1 atom of oxygen (O). The chemical composition of water may be interpreted as a 2:1 ratio of hydrogen atoms to oxygen atoms. Different types of chemical formulas are used to convey composition information, such as an empirical or molecular formula. Nomenclature can be used to express not only the elements present in a compound but their arrangement within the molecules of the compound. In this way, compounds will have unique names which can describe their elemental composition. Composite mixture The chemical composition of a mixture can be defined as the distribution of the individual substances that constitute the mixture, called "compon ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transparency (optics)
In the field of optics, transparency (also called pellucidity or diaphaneity) is the physical property of allowing light to pass through the material without appreciable scattering of light. On a macroscopic scale (one in which the dimensions are much larger than the wavelengths of the photons in question), the photons can be said to follow Snell's law. Translucency (also called translucence or translucidity) allows light to pass through, but does not necessarily (again, on the macroscopic scale) follow Snell's law; the photons can be scattered at either of the two interfaces, or internally, where there is a change in index of refraction. In other words, a translucent material is made up of components with different indices of refraction. A transparent material is made up of components with a uniform index of refraction. Transparent materials appear clear, with the overall appearance of one color, or any combination leading up to a brilliant spectrum of every color. The opposite ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brittle
A material is brittle if, when subjected to stress, it fractures with little elastic deformation and without significant plastic deformation. Brittle materials absorb relatively little energy prior to fracture, even those of high strength. Breaking is often accompanied by a sharp snapping sound. When used in materials science, it is generally applied to materials that fail when there is little or no plastic deformation before failure. One proof is to match the broken halves, which should fit exactly since no plastic deformation has occurred. Brittleness in different materials Polymers Mechanical characteristics of polymers can be sensitive to temperature changes near room temperatures. For example, poly(methyl methacrylate) is extremely brittle at temperature 4˚C, but experiences increased ductility with increased temperature. Amorphous polymers are polymers that can behave differently at different temperatures. They may behave like a glass at low temperatures (the glassy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal
A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typically ductile (can be drawn into wires) and malleable (they can be hammered into thin sheets). These properties are the result of the ''metallic bond'' between the atoms or molecules of the metal. A metal may be a chemical element such as iron; an alloy such as stainless steel; or a molecular compound such as polymeric sulfur nitride. In physics, a metal is generally regarded as any substance capable of conducting electricity at a temperature of absolute zero. Many elements and compounds that are not normally classified as metals become metallic under high pressures. For example, the nonmetal iodine gradually becomes a metal at a pressure of between 40 and 170 thousand times atmospheric pressure. Equally, some materials regarded as metals ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanophase Copper
Nanophase materials are materials that have grain sizes under 100 nanometres. They have different mechanical and optical properties compared to the large grained materials of the same chemical composition. Transparency and different transparent colours can be achieved with nanophase materials by varying the grain size. Nanophase materials *Nanophase metals usually are many times harder but more brittle than regular metals. ** nanophase copper is a superhard material ** nanophase aluminum ** nanophase iron is iron with a grain size in the nanometer range. Nanocrystalline iron has a tensile strength of around 6 GPA, twice that of the best maraging steels. *Nanophase ceramics usually are more ductile and less brittle than regular ceramics. Footnotes External links Creating Nanophase Materials ''Scientific American'' (subscription required) Nanophase Materials ''Michigan Tech'' ''Louisiana State University Louisiana State University (officially Louisiana State University and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanophase Aluminum
Nanophase materials are materials that have grain sizes under 100 nanometres. They have different mechanical and optical properties compared to the large grained materials of the same chemical composition. Transparency and different transparent colours can be achieved with nanophase materials by varying the grain size. Nanophase materials *Nanophase metals usually are many times harder but more brittle than regular metals. ** nanophase copper is a superhard material ** nanophase aluminum ** nanophase iron is iron with a grain size in the nanometer range. Nanocrystalline iron has a tensile strength of around 6 GPA, twice that of the best maraging steels. *Nanophase ceramics usually are more ductile and less brittle than regular ceramics. Footnotes External links Creating Nanophase Materials ''Scientific American'' (subscription required) Nanophase Materials ''Michigan Tech'' ''Louisiana State University Louisiana State University (officially Louisiana State University and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanophase Iron
Nanophase materials are materials that have grain sizes under 100 nanometres. They have different mechanical and optical properties compared to the large grained materials of the same chemical composition. Transparency and different transparent colours can be achieved with nanophase materials by varying the grain size. Nanophase materials *Nanophase metals usually are many times harder but more brittle than regular metals. ** nanophase copper is a superhard material ** nanophase aluminum ** nanophase iron is iron with a grain size in the nanometer range. Nanocrystalline iron has a tensile strength of around 6 GPA, twice that of the best maraging steels. *Nanophase ceramics usually are more ductile and less brittle than regular ceramics. Footnotes External links Creating Nanophase Materials ''Scientific American'' (subscription required) Nanophase Materials ''Michigan Tech'' ''Louisiana State University Louisiana State University (officially Louisiana State University and ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nanophase Ceramic
Nanophase ceramics are ceramics that are nanophase materials (that is, materials that have grain sizes under 100 nanometers). They have the potential for superplastic deformation. Because of the small grain size and added grain boundaries properties such as ductility, hardness, and reactivity see drastic changes from ceramics with larger grains. Structure The structure of nanophase ceramics is not too different than that of ceramics. The main difference is the amount of surface area per mass. Particles of ceramics have small surface areas, but when those particles are shrunk to within a few nanometers, the surface area of the same amount of a mass of a ceramic greatly increases."What's So Special about the Nanoscale?" nano.gov. Retrieved December 1, 2014. So in general, nanophase materials have greater surfa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ductile
Ductility is a mechanical property commonly described as a material's amenability to drawing (e.g. into wire). In materials science, ductility is defined by the degree to which a material can sustain plastic deformation under tensile stress before failure. Ductility is an important consideration in engineering and manufacturing. It defines a material's suitability for certain manufacturing operations (such as cold working) and its capacity to absorb mechanical overload.. Some metals that are generally described as ductile include gold and copper. However, not all metals experience ductile failure as some can be characterized with brittle failure like cast iron. Polymers generally can be viewed as ductile materials as they typically allow for plastic deformation. Malleability, a similar mechanical property, is characterized by a material's ability to deform plastically without failure under compressive stress. Historically, materials were considered malleable if they were am ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ceramic
A ceramic is any of the various hard, brittle, heat-resistant and corrosion-resistant materials made by shaping and then firing an inorganic, nonmetallic material, such as clay, at a high temperature. Common examples are earthenware, porcelain, and brick. The earliest ceramics made by humans were pottery objects (''pots,'' ''vessels or vases'') or figurines made from clay, either by itself or mixed with other materials like silica, hardened and sintered in fire. Later, ceramics were glazed and fired to create smooth, colored surfaces, decreasing porosity through the use of glassy, amorphous ceramic coatings on top of the crystalline ceramic substrates. Ceramics now include domestic, industrial and building products, as well as a wide range of materials developed for use in advanced ceramic engineering, such as in semiconductors. The word "'' ceramic''" comes from the Greek word (), "of pottery" or "for pottery", from (), "potter's clay, tile, pottery". The earliest kno ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
