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Technologies for Materials Types of Materials Industrial Chemicals Metals and alloys Ceramics and glasses Polymers and plastic materials Composite materials Semi-conductors Superconductors Some Products that Fulfill Human Needs and Wants Tires

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types of materials
Types of Materials
  • Industrial Chemicals
  • Metals and alloys
  • Ceramics and glasses
  • Polymers and plastic materials
  • Composite materials
  • Semi-conductors
  • Superconductors
slide3

Some Products that Fulfill Human Needs and Wants

Tires

http://telstar.ote.cmu.edu/environ/m3/s4/matdecmak.shtml

slide4

Chemical Substances Required in Large Quantities to Produce Materials that Fulfill Human Needs and Desires

http://telstar.ote.cmu.edu/environ/m3/s4/matdecmak.shtml

slide5

Chemical Industry

Broadly defined, the chemical industry accounts for 30-40% of the Gross National Product (GNP)

Chenier, Industrial Chemistry, 2nd, VCH, 1992, 5

slide6
U.S. Production of Top 10 Chemicals (x 109 lb.) - 1997

Sulfuric Acid 95.58

Nitrogen 82.88*

Oxygen 64.84*

Ethylene 51.08

Lime 42.56

Ammonia 38.39

Propylene 27.53

Phosphoric Acid 26.83

Ethylene Dichloride 26.29

Sulfur 26.24

Total for Top 50 Chemicals 729.36

C&EN, June 29, 1998

metals
Metals
  • Due to reactions with atmospheric O2, most metals occur as cations in ionic substances: Fe2O3 CaCO3,Al2O3
  • A pure metal is obtained by its cation gaining electrons (called reduction)
  • Iron occurs as oxide and is reduced by carbon to produce iron or structural steel (iron with carbon dissolved in it)
slide8

Production

Of Iron and

Steel in a

Blast Furnace

Garland, Chemistry of Our World, MacMillan, NY, 1975, 352

slide9

Production of Steel

Garland, Chemistry of Our World, MacMillan, NY, 1975, 357

slide10

Electrolytic Production of Al by Hall Process

2 Al2O3 => 4 Al + 3 O2

Garland, Chemistry of Our World, MacMillan, NY, 1975, 351

alloys
Alloys
  • Solid solutions of elements (usually metals) dissolved in a metal
  • Alter the properties of the original metal in some desired manner
corrosion
Corrosion
  • Corrosion is oxidation (loss of electrons) of a metal - 20% of iron must be replaced annually due to rusting
  • Corrosion of iron requires water and O2
  • 2 Fe + O2 + 2 H2O => 2 Fe(OH)2 4 Fe(OH)2 + O2 => 2 Fe2O3 + 4 H2O
  • Prevented by coating iron with paint or Zn (galvanizing) - ZnO more dense
ceramics and glasses
Ceramics and Glasses
  • Ceramics are substances formed by heating mixtures of ionic substances to high temperatures
  • Frequently involves oxides that are able to resist further oxidation
  • Most common involve clay Al2O3.2SiO2.2H2O
slide16

*

*Glasses are amorphous (do not have a repeating structure) while ceramics are crystalline (have a repeating structure).

Venugopalan, Chemistry and our World, Harper and Row, NY, 1975, 188

slide17

Ceramic - crystalline structure

Glass - amorphous structure

Si = red, O = gray, Na = yellow

Fine/Beal, Chemistry for Engineers and Scientists, Saunders, NY, 1990, 694

plastics
Plastics
  • Long chain-like structures (polymers) composed of individual repeating units (monomers)
slide19

Polyethylene (polymer)

Ethylene (monomer)

Tro, 377

polyethylene
Polyethylene
  • Thermoplastic - softens when heated
  • Addition polymer - monomer units combine without eliminating any atoms
  • High density (HDPE) has straight chains while low density (LDPE) has branches
  • Substitution of one or more H atoms produces derivatives with different properties
copolymers
Copolymers
  • Two types of monomers are combined- chains composed of alternating units
  • Condensation polymer - monomer units combine by expelling a small molecule such as water
slide24

Nylon

Tro, 382

elastomer
Elastomer
  • Polymer that stretches easily and returns to its original shape (rubber)
  • Natural rubber is polyisoprene
  • Vulcanization involves heating rubber with S which cross links chains
slide30

Synthetic Rubber

Venugopalan, Chemistry and our World, Harper and Row, NY, 1975, 244

composites
Composites
  • Combination of high strength fibers (of glass, graphite, or ceramics) held together by a polymer
  • Fiber provides support and polymer protects fibers from breaking
  • Fiber-glass is glass fiber in polyester - used in car panels, tennis rackets, molded chairs, boat hulls, etc
slide32

Sports Car with a Composite Body

Hill/Kolb, Chemistry for Changing Times, 9th, Prentice Hall, NJ, 2001, 283

semi conductors
Semi-conductors
  • A semiconductor is a substance that conducts electricity to a very limited extent at room temperature, but its conductivity increases with increasing temperature, or when “doped” with appropriate other substances
  • Si forms covalent bonds with 4 Si atoms around itself and has no electrons free to move and conduct electricity - insulator
slide34

Si as a Semi-conductor

http://electronics.howstuffworks.com/diode1.htm

doping silicon
Doping Silicon
  • Doping (mixing a small amount of another substance into the silicon crystal) increases its electrical conductivity
  • Elements from 3A and 5A families can be used as dopants for 4A semiconductors
slide36

3,5 - Dopants

http://electronics.howstuffworks.com/diode2.htm

slide37

Electron Donor and Acceptor Doped Si-Crystals

N-type semi-conductor (negative)

P-type semi- conductor (positive)

Hill/Kolb, Chemistry for Changing Times, 8th, Prentice Hall, NJ, 1998, 375

slide38

A diode is the simplest possible semiconductor device. A diode allows current to flow in one direction but not the other.

http://electronics.howstuffworks.com/diode3.htm

transistor
Transistor
  • A transistor is created by using three doped layers (PNP or NPN) rather than the two layers used in a diode
  • A transistor can act as a switch or an amplifier - applying a small current to the center layer of the sandwich, causes a much larger current to flow through the sandwich as a whole

http://electronics.howstuffworks.com/amplifier1.htm

silicon chip
Silicon Chip
  • A piece of silicon that can hold thous-ands of transistors
  • With transistors acting as switches, you can create Boolean gates, and with Boolean gates you can create microprocessor chips and hence computers

http://electronics.howstuffworks.com/diode4.htm

superconductors
Superconductors
  • An element, inter-metallic alloy, or compound that will conduct electricity without resistance below a certain temperature, Tc
  • Require low temperatures to slow down molecular vibrations sufficiently to facilitate unimpeded electron flow

http://superconductors.org/Type1.htmv

slide44

History of Superconductors

Scientific American, January 1994, 18

slide45

Type 1 superconductor, Tc is 0 - 10 K, consist of metals and metalloids that show some conductivity at room temperature

Type 2 superconductor, Tc is 10 - 138 K, consist of metallic compounds and alloys

http://superconductors.org/Uses.htm

slide47

Meissner Effect

Meissner effect: The expulsion of all magnetic fields from the interior of a superconductor. Magnetic field induces electric current in the superconductor that produces a magnetic field in the superconductor having same orientation as the magnet. Repulsions of like poles cause the magnet to levitate.

External lines of force wrap around the magnet and hold it in place - “magnetic pinning”

http://hyperphysics.phy-astr.gsu.edu/hbase/solids/maglev.html

slide48

The Yamanashi MLX01 MagLev Train

A 5-car MLX01 MagLev Train achieved a sustained velocity of 343 miles/hr on 4/14/99

http://superconductors.org/Uses.htm

meissner effect
Meissner Effect
  • When a substance becomes a superconductor, it is repelled by an external magnetic field
  • If a small magnet is placed on top of a superconductor, the magnet levitates, i.e., it is repelled upward (floats) but is held within the space of the magnetic field (magnetic pinning)
slide51

U.S. Production of Top 50 Chemicals (x 109 lb.) - 1997

Total Organics 279.17

Total Inorganics 450.19

Grand Total 729.36