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99 Cards in this Set
- Front
- Back
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What are the three main classes of materials?
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(1) Metallic
(2) Polymer (plastic) (3) Ceramic materials |
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What are the two secondary classes of materials?
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(a) composite materials
(b) electronic materials |
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What are the main properties of metallic material? (type, bond, atomic structure)
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a. inorganic
b. metal c. orderly crystaline structure d. thermal and electric conductors e. strong, tough f. deformable but flexible g. reflective h: BOND: metallic |
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What are five example metallic materials?
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1. iron (fe)
2. copper (Cu) 3. aluminum (Al) 4. nickel (Ni) 5. titanium (Ti) |
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How do metals conduct electricity?
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In a metallic bond, electrons are shared in a delocalized manner. Thus one electron jump will cause a domino reaction. Thus electric flow; Current (I).
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What are the main properties of polymeric material? (type, bond, atomic structure)
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- organic (carbon containing)
- long molecular chains - non-crystaline structure (mostly) - poor conductors - good insulators - low densities - low softening / decomposition - BOND by: VDW |
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What are the main properties of Ceramic materials? (type, bond, atomic structure, how made)
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- organic (carbon containing)
- metallic and non-metallic material ionically bound together - structure: crystaline, non-crystaline, or both - physical: hard, high temp, brittle - (also: light, strong, hard, heat-resistant) - usually made by: SINTERING |
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How are ceramic materials bonded?
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Ionic bonding
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What is the atomic structure of ceramic materials?
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structure: crystaline, non-crystaline, or both
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How are ceramic materials usually made?
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Sintering
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What is the molecule for glass?
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SiO2 - Silica
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What are the defining properties of glass?
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- transparent
- supercooled liquid (acts like solid) - electrically insulating - brittle |
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What is an example of a Semi-Conducting material?
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Si - Silicone
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What is the main property of a Semi-conductor?
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electrical resistivity
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How are semiconductors mainly used? (list three)
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(main) integrated circuits
(others:) - LED's - solid state lasers - MOS (Metal Oxide Silicon) technology |
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What is a SUPERconductor?
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a material that - below a critical temperature, will pass an electrical current with Zero resistance
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What are examples of Superconductors?
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- Nb3Sn (25k)
- YBa2Cu3O4 (90k) |
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What is a COMPOSITE material? What are the main physical properties?
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- combined material.
- Solid enough to hold together, loose enough to provide gaps. - High strength:weight ratio |
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List one main example of a composite material.
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Fiberglass (graphite fibers + epoxy)
- use in: a graphite golf club |
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What is a natural composite material? eg.?
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- fibers bound by natural glue
- bone, wood, teeth |
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What type of material is Polyethylene?
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Plastic / polymer
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How are metals/metallic alloys fabricated?
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- Casting: L -> S
- Rolling: S -> S - Forging: S ->S |
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Give examples of cast materials:
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- ice (H20)
- iron (Fe) - many metals |
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Give an example of a rolled material:
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- Al
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How are ceramics made?
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Sintering (firing)
S->S |
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How is glass made?
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L-> S
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Describe the sintering process:
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A ceramic process in which powder particles are packed into a mold and heated to a high temperature (~1500 K)
s > s |
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describe sputtering:
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bombarding a "target" surface in a vacuum with atoms or ions to build material up
s > v > s |
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describe rolling:
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send material through press until it things / "rolls out" enough.
eg: Al foil s > s |
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describe casting:
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pour liquid into mold till it solidifies
L > S |
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describe chemical vapor deposition
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a thin film deposition technique in which reactions in the gas phase create products which then deposit on a substrate
v > s |
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what is injection molding?
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a polymer process by which hot plastic is forced into cavity/mold where it cools into solid
l > s |
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what is electron-beam evaporation?
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a vapor deposition technique in which the source material is heated by means of an impinging electron beam to a sufficiently high temperature that it evaporates
s > v > s |
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describe the Czochralski Method:
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Used to create large silicon boules (long cylinders) from which single crystal silicon wafers are cut.
Basically - dip a single crystal into liquid Si while spinning it until you have a pure boule L > S |
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what is Vapor-Liquid-Solid growth?
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a method to grow a semiconductor nanowire from an appropriate gas by way of a liquid droplet.
v>l>s |
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how is fiberglass composite material made?
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embedding glass fibers in epoxy
l > s |
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how are silicone wafers made?
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Czochralski method
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how are semiconductor nanowires formed?
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vapor - liquid - solid growth
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What process makes Co layers for harddrives?
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sputtering
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how are semi-conductors and thin films often made?
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Chemical deposition process.
v>s via hole |
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Si(4)HCl(4) is made by what process?
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chemical vapor deposition
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What are 4 types of nano materials? Try to give examples
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1. nano particles
2. nano tubes (carbon nanotubes) 3. nano wires (Si, Germanium Ge) 4. nano ribbons |
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Describe properties of "fumed silica"
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- Fe(NoO3)*9H20
- Heat to 900 degrees c in Ch4 - Fe Nanopart |
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Describe Cobalt nanoparticle
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- CoNO3*6420
- heat to 900 C in CH4 - Co nanopart |
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Name three types of nanotubes
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- CH(4)
- C(2)H(2) - C(2)H(6) *all different carbon and hydrogen combination |
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How do you grow a nanotube?
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- add metal catalyst with New Particles
- can grow either up or downwards - start with one seed crystal |
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What are two most impt. examples of nanowire materials?
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Si, Ge
both are semiconductors - SiH4 - GeH4 |
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How are nanowires made?
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- put nano particles on magnetic substrate
- let them grow |
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def: Anion
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Negatively charges ion, they have an extra electron.
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how do anions function in relation to other ions?
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as anions are negatively charged, they can affect other ions by dispelling their extra electron and thus changing the whole environment's electric landscape
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def: Cation
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positively charged ion.
has lost an electron. |
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Do not let alkaline metals touch ____
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Salt. Or noble gases. They will mess up the following materials:
- boron - Al - Galium |
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def: Ionic Bond
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bond between positively and negatively charged ions
- transfers electrons - coulombic charge |
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def: covalent bond
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materials bound together because they share an electron
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examples of a covalent bond?
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- diamond
- semi-conductors Si, Ge - methane: (CH4) Bonds withing molecule are strong |
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def: metallic bond
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-makes rows, orderly, 3-D crystals
-sharing of electrons in delocalized manner -non-directional |
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What are the 2 types of secondary bonds?
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1) Van derWaals Force
2) Hydrogen Bonds |
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Van der Waals Force (def)
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Def: at any given time there are more electrons on one side of the proton than the other side - so there is thus a momentary attraction.
Weak force, but important |
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Examples of Van der Waals force in action
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1) Gecko Feet
2) PVC (Polyvinyl chloride) 3) Dry Ice (CO2) 4) Polyethylene, PET 5) ALL PLASTICS |
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What is the bonding type for all "poly"/ platic materials?
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VDW
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What is the bonding for all ceramic materials?
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Ionic
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What is the eqn for interaction energy?
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V = -A/a^m + B/a^n
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What is an expression for the force between atoms?
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- The derivative of V(t)
- d/da(-A^-m+Ba^-n) = mA/a^(m+1) - nB/a^(n+1) |
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Example of Close-packed structure
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metallic structure
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(2) Examples of ionic bonding:
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- MgO - magnesium Oxide
- Al203 - Aluminum oxide |
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(6) examples of covalently bonded materials:
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- Si - silicone
- Ge - germanium - GaN - galium nitrate - AlN - aluminum nitrate - AlP - Alkaline Phosphate |
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(4) examples of metallically bonded materials
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Al - aluminum
W -- ? |
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(1) example of a hydrogen bond
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H20 - water
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What is the atomic layering sequence present in FCC structure?
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ABCABCABC
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What is the atomic layering sequence present in HCP structure?
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ABABABAB
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Which atomic structures are close-packed?
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FCC - face centered cubic
and HCP - Hexagonal Close Packed |
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Which is "loose"
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BCC - body centered cubic
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How do you calculate Atomic Packing Factor?
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APF = volume of atoms in unit cell/volume of unit cell
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radius to cube length (a) ratio for BCC:
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a=4R/3^.5
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radius to cube length (a) ratio for FCC:
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a=4R/2^.5
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APF for BCC:
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APF = .68 (less dense)
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APF for FCC
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APF = .74 (more dense)
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What type of material structure does ALUMINUM have?
(bcc/fcc/hcp) |
FCC
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What type of material structure does COPPER have?
(bcc/fcc/hcp) |
FCC
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What type of material structure does LEAD have?
(bcc/fcc/hcp) |
FCC
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What type of material structure does NICKEL have?
(bcc/fcc/hcp) |
FCC
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What type of material structure does CHROMIUM have?
(bcc/fcc/hcp) |
BCC
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What type of material structure does IRON have?
(bcc/fcc/hcp) |
BCC
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What type of material structure does SODIUM have?
(bcc/fcc/hcp) |
BCC
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What type of material structure does TUNGSTEN have?
(bcc/fcc/hcp) |
BCC
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What type of material structure does CADMIUM have?
(bcc/fcc/hcp) |
HCP
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What type of material structure does ZINC have?
(bcc/fcc/hcp) |
HCP
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What type of material structure does MAGNESIUM have?
(bcc/fcc/hcp) |
HCP
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What type of material structure does TITANIUM have?
(bcc/fcc/hcp) |
HCP
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What happens with an allotropic material? Give an example
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It contracts from BCC to FCC structure with temperature
example: iron Fe |
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What is an example of a material that changes from HCP > FCC?
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Cobalt, when temperatures are greater thatn 447C
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Main geometric attributes of HCP structure:
(how many bonds between particles?) |
- formed by close packed bonds
- 6 bonds per atom in each plane - 12 bonds/atom |
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What type of material structure does Silver (Ag) have?
(bcc/fcc/hcp) |
fcc
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What type of material structure does gold (Au) have?
(bcc/fcc/hcp) |
fcc
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What type of material structure does Palladium (Pd) have?
(bcc/fcc/hcp) |
fcc
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What type of material structure does Platinum (Pt) have?
(bcc/fcc/hcp) |
fcc
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height and "a" measure for unit cell of HCP in relation to atomic radius?
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a=2R
c "hexagon height" c=(8/3)^.5 a |
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Do an FCC unit cell calculation
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Density of fcc solid = mass/unitvolume
Al = #atoms/unit cell * unit cells *atomic weight / a I think ?? |
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APF=
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volume occupied by atoms/total volume
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