Bonding Flashcards

1
Q

3 primary bond types

A

Ionic
Covalent
Metallic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

2 secondary bond types

A

Van see waals

Hydrogen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Main bonds in metals/alloys

A

Metallic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Main bonds in ceramics

A

Ionic/ covalent

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Main bonds in polymers (2 aspects)

A

Covalent bonds between carbon atoms in chains

Van der waals or hydrogen bonds between chains

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Elastic modulus and melting point are a function of

A

Bond energy

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

3 assumptions for materials structure

A

Atoms are close packed hard spheres
Atoms are packed two dimensionally in atomic planes
Planes are stacked to form crystals

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

3 arrangements of atoms are

A

Face centered cubic
Hexagonal close packed
Body centred cubic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Main features of FCC

A

Atom in each corner and on each face
Close packed
More slip directions so more ductile

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Main features of BCC

A

Atom on each corner. 1 atom in centre

Non close pack structure

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

3 atom arrangements in order of ductility (best-worst)

A

FCC
BCC
HCP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

3 atom arrangements in order of strength (best-worst)

A

HCP
BCC
FCC

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What determines density( 3)

Which is most significant

A

Atomic weight ( most significant)
Size of atoms
Atom packing

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does crystalline mean

A

Regularly repeating pattern of structural units

Most materials are crystalline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

FCC and HCP take up how much available space

A

74%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

BCC takes up how much available space

17
Q

Ferrite (alpha) is iron at what temp with what packing

A

Room temp

BCC

18
Q

Austenite is iron at what temp and with what packing

A

Above 912 c

FCC

19
Q

Ferrite (delta)is iron at what temp and with what packing

A

Above 1394 c

BCC

20
Q

Above what temp does iron become liquid

21
Q

Why do u quench iron

A

Stops carbon diffusion

Creates new structure which is harder to deform

22
Q

What is another name for noncrystalline

23
Q

Key feature of metallic crystal structure and 3 reasons why

A

Densely packed as
Only 1 element so atomic radii is constant
Metallic bonding is not directional
Electron clouds shield cores from each other

24
Q

Atomic packing in glasses

A

Base often amorphous silica

Rapid cooling means the amorphous structure achieved by melting is maintained

25
Crystal structure of ceramics (?2 main facts)
Composed of at least 2 elements | Have cations and anions
26
Most materials are polycrystalline. Each crystal is called a .... with .... separating each one
Grain | Grain boundaries
27
4 crystalline imperfections
Vacancies Solute atoms Dislocations Grain boundaries
28
Polymers are made up of.... | they can be either .... or ....
Long chains of carbon atoms | Amorphous, crystalline or both
29
Polymorphism is
When materials change from one structure to another
30
Fullerenes are
Spherical cluster of 60 carbon atoms
31
Carbon nanotubes are
Sheet of graphite rolled into a tube. The ends are capped with fullerene hemispheres
32
Graphene is
A single atomic layer of graphite composer of hexagonally bonded carbon atoms
33
Diamond is only .... at
Meta stable | Room temp and pressure
34
Shape memory alloys are
Materials that show a memory when they are deformed /heated/ cooled due to reversible change in structure