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51 Cards in this Set

  • Front
  • Back
six different property classifications of materials that determine their applicability
1. Metals
2. Ceramics
3. Polymers
4. Composites
5. Semiconductors
6. Biomaterials
Ceramics
Metallic and nonmetallic
Most frequently nitrides, oxides and carbides.
Insulative to the passage of electricity and heat
Resistant to high temp and harsh environments.
More then metals and polymers.
Metals
Combo of Metallic elements
Large number of non localized electrons (not bound to a particular atom)
Good conductors of electricity and heat.
Strong and deformable
Polymers
Plastic and rubber materials.
Organic compounds based on carbon, hydrogen, and nonmetallic elements
Large Molecular structure
Low density. flexible.
Composites
Consist of more then one type of material.
Fiberglass
Strength and flexibility
Recent developments include.
Semiconductors
utilized because of their unusual electrical characteristics.
electrical properties are in the middle of electrical and insulator conductors.
Sensitive to impure atoms.
Biomaterials
Implantation into body
Must not produce toxins and be compatible with body tissue.
All 5 materials can be used as biomaterials.
Advanced materials
materials that are utilized for high technology.
Smart Materials



components include
Materials are able to sense changes in their environments and then respond to these changes in predetermined manners
-sensor (that detects input)
-actuator (which preforms responsive and adaptive function.)
Actuator
performs re9sponsive and adaptive functions. are smart material.
Nanotechnology

type of approach
ability to carefully arrange atoms which provide opportunity to develop mechanical, electrical, magnetic, and other properties that are not otherwise possible.
“bottom-up” approach
Nonrenewable resources

which leads to
Polymers

1) the discovery of additional reserves
2) the development of new materials with renewable properties.
3) increased recycling efforts and the development of new recycling technologies.
four components that are involved in the design, production, and utilization of materials
Processing-

Structure- arrangement of its internal components.

Properties- reaction when exposed to external stimuli

Performance
three classifications of solid materials
metals, ceramics, and polymers
Criteria for picking a material
1. Maximum or ideal combination of properties (strength and ductility)
2. deterioration of material properties (lastingness)
3. economics: What will the finished product cost?
atomic weights of the elements generally not integers
1. atomic masses are usually not integers
2. taken as an average with the isotopes
atomic number

atomic mass
number of electrons

sum of protons and neutrons
valence electrons determin
chemical, mechanical, thermal and optical properties
n
principal level (1,2,3,etc)
l
subsidary orbital (s,p,d,f) (0,1,2,3,4)
ml
magnetic (1,3,5,7) from -l to +l
ms
spin (1/2, -1/2)
electrons tend to occupy
lowest energy level possible
valence shell completley filled:

less then half filled

more then half filled

other
stable


give up electron

gain electron

share electron
Electropositive elements:

electronegative ele
give up electrons to become cations
acquire elec. to become anions
Metallic bonding occurs between
have
low electronegative ele.

have loosly held electrons in electron sea.
predominant bonding in ceramics
ionic
Secondary bonding arises from
interaction between dipoles.
Ionic Bonding
energy:
bond energy:large,
metal and nonmetal.
non directional. ceramics
Covalent
large:
small:
Variable.two non metals.
large: Diamond small: bismuth
directional.
semiconductors, ceramics. polymer chains
Metallic
large:
small:
large: Tungsten
Small: mercury
nondirectonal. metals
Secondary aka:
van Der Waals
Directional
interchain (polymer. inermolectular.
Ceramics, type of bonding
ionic and covalent. Large bond energy
Metals, type of bonding:
variable bond energy
polymers:
covalent and secondary.
secondary bonding dominates.
dense regular packed structures
have lower energy
Metallic crystal structures:
densly packed
Dense packing does what?
1. reduces empty spaces
2. highest number of coordination
3. non directional
4. minimum potential energy favored.
FCC
coordionation number:
atoms in unit cell:
length:
atomic packing factor
12
4
2Rsqrt(2)
.74
BCC
coordination numer
atoms in unity cell
length
atomic packing factor
8
2
4R=sqrt(3)*a
.68
HPC
coordionation number:
atoms in unit cell:
length:
atomic packing factor
12
6

.74
Stable ceramic crystal structures form when
anions are in contact with caiton
Cesium Chloride coordination number:
8
Zinc Blende coordination number:
4
Silicates primarily composed of :
ex:
usually known as:
Si and O

rocks, soil, clay
ax type crystal structure.
Polymorphism
material can exist as more then one type of crystal structure.
allotrophy
polymorphism of elemental solids
Carbon exists in

carbon nanotube
polymorphic form

single layer of graphite
Graphite
composed of layers of hexagon carbon structures
xray defraction used to


occurs when
investigate atomic and molecular arrangement in solids

wave scatter from a series of regular spaced particles. have spacing compareable to wavelength of wave.
SC

coordination number

apf
simple cubic crystal structure.

rare due to low packing density


6
.52