Nanomaterials

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Anonymous
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12267
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Nanomaterials
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2010-03-28 19:10:01
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Nanomaterials
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Nanomaterials
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  1. Metals
    Metals account for ~ 2/3 of all the elements and about 24% of the mass of the planet

    The key feature that distinguishes metals from non-metals is bonding. Metallic materials have free electrons that are free to move easily from one atom to the next.
  2. Ceramics
  3. an inorganic, nonmetallic solid that is prepared from powdered materials, is fabricated into products through the application of heat, typically crystalline in nature and are compounds formed between metallic and nonmetallic elements such as aluminum and oxygen (alumina-Al2O3), calcium and oxygen (calcia - CaO), and silicon and nitrogen (silicon nitride-Si3N4).
  4. Polymers
    Organic compounds poly mers

    plastics and elastomers



    The term ‘thermoplastic’ indicates that these materials melt on heating and may be processed by a variety of molding and extrusion techniques. Alternately, ‘thermosetting’ polymers can not be melted. Thermosetting polymers include alkyds, amino and phenolic resins, epoxies, polyurethanes, and unsaturated polyesters.

    Rubber is a natural occurring polymer
  5. Composite
    a combination of two or more distinct materials, each of which retains its own distinctive properties, to create a new material with properties that cannot be achieved by any of the components acting alone.

    For example, concrete is a composite because it is a mixture of Portland cement and aggregate. Fiberglass sheet is a composite since it is made of glass fibers imbedded in a polymer.
  6. Crystalline vs Amorphous Structures
    Cystralline show both long and short range order

    Amorphous show short but no long range order
  7. BCC
  8. Molybdenum
    • Chromium
    • Tungsten
  9. FCC
  10. Gold
    • Copper
    • Aluminum
  11. HCP
  12. Cobalt
    Titanium
  13. Factors that affect structure
    1. Size of the atoms

    2. Atomic bonding
  14. Making the compound into something useful
    • Polymerize into a liquid
    • Solidify from a melt
    • Condense from a vapor
    • Sinter from a powder
  15. Solidification
    Compounds freeze as the temperature decreases.

    Shapes created by the container.

    • Examples:
    • Ice cubes,


    To grow a single crystal the conditions are controlled so that atoms attach to a “nucleus” of the crystal without starting a new crystal.

    Think of the rock candy experiment
  16. Morphology
    Making the compound into something useful.

    Elements and compounds are often melted then crystallized, a process that results in polycrystalline solids.

    • Morphology is the internal shape of constituents of a solid
    • size, shape, orientation of individual crystals
    • arrangements of domains within the solid
    • arrangements of different phases or compounds
  17. Sintering a powder:
    shaping a powder into a shape then heating. Surface energy drives the material to coalesce and the particles to grow by solid state atomic motion
  18. Shape Forming Examples
    Medieval swords: fire and bodily fluids (Metal casting)

    Rodin & Chinese/Baroque porcelain (MOld)

    Cake decorating (Extrusion)
  19. Properties
    • electronic : conductivity, band gap
    • optical: color, absorbance, emission
    • dielectric: ferroelectric, piezo electric, fflexo electric
    • mechanical: hardness, strength, toughness
    • thermal: expansion, conduction
    • chemical: reactivity
    • thermodynamic: surface energy, phase stability
  20. Summary
    Materials can be classified as ceramics, metals, polymers & composites

    • Solid materials are crystalline or amorphous
    • crystalline: short range and long range order of the atoms
    • amorphous: may have short range order, no long range order

    • Crystalline materials
    • structure depends on how the atoms are ordered
    • ordering depends on size of and bonding between atoms

    • Morphology is the internal shape of constituents of a solid
    • size, shape, orientation of individual crystals
    • arrangements of domains within the solid
    • arrangements of different phases or compounds
    • Properties depend on crystal structure and morphology

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