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51 Cards in this Set
- Front
- Back
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six different property classifications of materials that determine their applicability
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1. Metals
2. Ceramics 3. Polymers 4. Composites 5. Semiconductors 6. Biomaterials |
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Ceramics
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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. |
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Metals
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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 |
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Polymers
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Plastic and rubber materials.
Organic compounds based on carbon, hydrogen, and nonmetallic elements Large Molecular structure Low density. flexible. |
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Composites
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Consist of more then one type of material.
Fiberglass Strength and flexibility Recent developments include. |
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Semiconductors
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utilized because of their unusual electrical characteristics.
electrical properties are in the middle of electrical and insulator conductors. Sensitive to impure atoms. |
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Biomaterials
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Implantation into body
Must not produce toxins and be compatible with body tissue. All 5 materials can be used as biomaterials. |
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Advanced materials
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materials that are utilized for high technology.
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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.) |
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Actuator
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performs re9sponsive and adaptive functions. are smart material.
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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 |
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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. |
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four components that are involved in the design, production, and utilization of materials
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Processing-
Structure- arrangement of its internal components. Properties- reaction when exposed to external stimuli Performance |
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three classifications of solid materials
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metals, ceramics, and polymers
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Criteria for picking a material
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1. Maximum or ideal combination of properties (strength and ductility)
2. deterioration of material properties (lastingness) 3. economics: What will the finished product cost? |
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atomic weights of the elements generally not integers
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1. atomic masses are usually not integers
2. taken as an average with the isotopes |
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atomic number
atomic mass |
number of electrons
sum of protons and neutrons |
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valence electrons determin
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chemical, mechanical, thermal and optical properties
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n
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principal level (1,2,3,etc)
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l
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subsidary orbital (s,p,d,f) (0,1,2,3,4)
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ml
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magnetic (1,3,5,7) from -l to +l
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ms
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spin (1/2, -1/2)
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electrons tend to occupy
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lowest energy level possible
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valence shell completley filled:
less then half filled more then half filled other |
stable
give up electron gain electron share electron |
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Electropositive elements:
electronegative ele |
give up electrons to become cations
acquire elec. to become anions |
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Metallic bonding occurs between
have |
low electronegative ele.
have loosly held electrons in electron sea. |
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predominant bonding in ceramics
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ionic
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Secondary bonding arises from
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interaction between dipoles.
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Ionic Bonding
energy: |
bond energy:large,
metal and nonmetal. non directional. ceramics |
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Covalent
large: small: |
Variable.two non metals.
large: Diamond small: bismuth directional. semiconductors, ceramics. polymer chains |
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Metallic
large: small: |
large: Tungsten
Small: mercury nondirectonal. metals |
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Secondary aka:
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van Der Waals
Directional interchain (polymer. inermolectular. |
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Ceramics, type of bonding
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ionic and covalent. Large bond energy
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Metals, type of bonding:
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variable bond energy
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polymers:
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covalent and secondary.
secondary bonding dominates. |
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dense regular packed structures
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have lower energy
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Metallic crystal structures:
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densly packed
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Dense packing does what?
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1. reduces empty spaces
2. highest number of coordination 3. non directional 4. minimum potential energy favored. |
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FCC
coordionation number: atoms in unit cell: length: atomic packing factor |
12
4 2Rsqrt(2) .74 |
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BCC
coordination numer atoms in unity cell length atomic packing factor |
8
2 4R=sqrt(3)*a .68 |
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HPC
coordionation number: atoms in unit cell: length: atomic packing factor |
12
6 .74 |
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Stable ceramic crystal structures form when
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anions are in contact with caiton
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Cesium Chloride coordination number:
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8
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Zinc Blende coordination number:
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4
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Silicates primarily composed of :
ex: usually known as: |
Si and O
rocks, soil, clay ax type crystal structure. |
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Polymorphism
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material can exist as more then one type of crystal structure.
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allotrophy
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polymorphism of elemental solids
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Carbon exists in
carbon nanotube |
polymorphic form
single layer of graphite |
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Graphite
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composed of layers of hexagon carbon structures
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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. |
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SC
coordination number apf |
simple cubic crystal structure.
rare due to low packing density 6 .52 |
