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FUNDAMENTALS OF MATERIAL SCIENCE > Structure And Properties Of Ceramics > Flashcards

Structure And Properties Of Ceramics Flashcards

1
Q

inorganic and nonmetallic materials

A

Ceramic

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2
Q

between metallic and non-metallic elements which the interatomic bonds are either totally ionic or predominantly ionic but having some covalent character

A

Ceramic

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3
Q

greek word keramikos, which means

A

Burnt stuff

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4
Q

crystal structures are generally more complex than those for metals

A

Ceramics

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5
Q

Two characteristics of the component ions on crystalline ceramic materials influence the crystal structure

A

magnitude of the electrical charge
sizes of the cations and anions

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6
Q

Why is it that some or the ceramics are predominantly ionic?

A

There crystal structure is electrically charged

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7
Q

Common ceramic materials are those in which there are equal numbers of cations and anions

A

AX Compound

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8
Q

Most common AX compound crystal structure

A

Rock salt

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9
Q

coordination number for both cations and anions is 6

A

Rock salt

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10
Q

coordination number is 8 for both ion types

A

Cesium chloride

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11
Q

AX structure is one in which the coordination number is 4

A

Zinc Blende

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12
Q

charges on the cations and anions are not the same

A

AmXp

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13
Q

Interstitial positions

A

Tetrahedral
Octahedral

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14
Q

Four atoms (three in one plane, and a single one in the adjacent plane) surround one type

A

Tetrahedral position

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15
Q

involves six ion spheres, three in each of the two planes

A

Octahedral position

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16
Q

AmBnXp types, which is found for magnesium aluminate or spinel (MgAl2O4)

A

Spinel structure

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17
Q

composed primarily of silicon and oxygen

A

Silicate

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18
Q

2 most common abundant element in Earth’s crust

A

Silica
Oxygen

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19
Q

most simple silicate material

A

Silicon dioxide or silica

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20
Q

three primary polymorphic crystalline forms of silica

A

Quartz
Cristobalite
Tridymite

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21
Q

Silica that exist as noncrystalline solid or glass having a high degree of atomic randomness, which is characteristic of the liquid

A

Fussed Silica or vitreous silica

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22
Q

oxides (B2O3, GeO2) may also form glassy structures

A

Network former

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23
Q

oxide additives

A

Network modifier

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24
Q

oxides, such as TiO2 and Al2O3, substitute for silicon and become part of and stabilize the network

A

Intermediate

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25
Q

addition _____________________ lowers the melting point and viscosity of a glass and makes it easier to form at lower temperatures

A

modifiers and intermediates

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26
Q

can be produced by the sharing of three oxygen ions in each of the tetrahedra

A

Layered silicate

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27
Q

ordinarily established by a second planar sheet structure having an excess of cations, which bond to these unbonded oxygen atoms from the Si2O5 sheet

A

Electroneutrality

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28
Q

basic structure is characteristic of the clays and other minerals

A

Sheet

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29
Q

Common clay mineral

A

Kaolinite

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29
Q

Common clay mineral

A

Kaolinite

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30
Q

made of a series of these double layers or sheets stacked parallel to each other and form small flat plates that are typically less than 1μm in diameter and nearly hexagonal

A

Crystal of kaolinite

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31
Q

Exist in 2 allopathic form

A

Carbon

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32
Q

Allopathic forms of carbon

A

Diamond
Graphite

33
Q

metastable carbon polymorph at room temperature and atmospheric pressure

A

Diamond

34
Q

variant of the zinc blende structure in which carbon atoms occupy all positions

A

Diamond

35
Q

structure of diamond is appropriately called?

A

diamond cubic crystal structure

36
Q

stable polymorph at ambient temperature and pressure

A

Graphite

37
Q

used to designate the types and concentrations of atomic defects in ceramics

A

Defect structure

38
Q

state that exists when there are equal numbers of positive and negative charges from the ions

A

Electroneutrality

39
Q

defect involves a cation–vacancy and a cation–interstitial pair

A

Frenkel defect

40
Q

defect found in AX materials is a cation vacancy–anion vacancy pair

A

Schottky defect

41
Q

created by removing one cation and one anion from the interior of the crystal and then placing them both at an external surface. Because the magnitude of the negative charge on the cation i

A

Schottky defect

42
Q

state for ionic compounds wherein there is the exact ratio of cations to anions as predicted by the chemical formula

A

Stoichiometry

43
Q

there is any deviation from this exact ratio

A

Nonstoichiometric

44
Q

occur for some ceramic materials in which two valence (or ionic) states exist for one of the ion types

A

nonstiochiometric

45
Q

What are the solid solution that the impurity atom can form in thr ceramic material?

A

Interstitial
Substitutional

46
Q

the ionic radius of the impurity must be relatively small in comparison to the anion

A

Interstitial

47
Q

substitutes for the host ion to which it is most similar in an electrical sense

A

Substitutional

48
Q

usually occurs by a vacancy mechanism in order to maintain charge neutrality in an ionic material

A

Diffusion

49
Q

Vacancies

A

Occurs in pairs
Form nonstoichiometric compound
Created by substitutional impurities

50
Q

One of the relatively simple ceramic phase diagrams

A

Aluminum oxide - chromium oxide

51
Q

has the same form as the isomorphous copper–nickel phase diagram, consisting of single liquid-phase and single solid-phase regions separated by a two-phase solid–liquid region having the shape of a blade

A

Aluminum oxide - chromium oxide

52
Q

it is frequently the case that the two components are compounds that share a common element

A

Binary-two component phase diagram

53
Q

One eutectic and 2 eutectoid is found gor this system

A

Zirconium oxide - calcium oxide

54
Q

zirconia material having a calcia content within the range cited

A

Partially stabilize zirconia

55
Q

Principle constituent of ceramui refactories

A

Silica and alumina

56
Q

consists of the formation and propagation of cracks through the cross section of material in a direction perpendicular to the applied load

A

Brittle fracture process

57
Q

Crack growth in crystalline ceramics:

A

Transgranular
Intergranular

58
Q

cracks propagate along specific crystallographic (or cleavage) planes, planes of high atomic density

A

Transgranular fracture

59
Q

measure of a ceramic material’s ability to resist fracture when a crack is present

A

Fracture toughness

60
Q

fracture of ceramic materials occur by the slow propagation of cracks, when stresses are static in nature

A

Static fracture

61
Q

This type of fracture is especially sensitive to environmental conditions, specifically when moisture is present in the atmosphere.

A

Static fatigue

62
Q

occurs at the crack tips

A

Stress corrosion process

63
Q

involves examining the path of crack propagation, as well as microscopic features of the fracture surface.

A

Fractographic study

64
Q

indicative of whether the ceramic piece was excessively weak or the in-service stress was greater than anticipated

A

Stress magnitude

65
Q

crack surface that formed during the initial acceleration stage of propagation is flat and smooth

A

Mirror region

66
Q

Surface features:

A

Mist
Hackle

67
Q

faint annular region just outside the mirror

A

Mist

68
Q

beyond the mist

A

Hackle

69
Q

has an even rougher texture

A

Hackle

70
Q

composed of a set of striations or lines that radiate away from the crack source in the direction of crack propagation

A

Hackle

71
Q

arc shaped, and they provide information regarding stress distributions and directions of crack propagation

A

Wallner line

72
Q

stress at fracture using this flexure test

A

Fractural strength

73
Q

modulus of rupture, fracture strength, or bend strength, an important mechanical parameter for brittle ceramics

A

Fractural strength

74
Q

occurs by the motion of dislocations.

A

Plastic deformation

75
Q

Reasons why ceramics are brittle

A

Covalent bond is strong
Limited number of slip
Dislocation structure is complex

76
Q

measure of a noncrystalline material’s resistance to deformation

A

Viscosity

77
Q

For some ceramic fabrication techniques, the precursor material is in the form of

A

Powder

78
Q

deleterious to the flexural strength for two reasons: (1) pores reduce the cross-sectional area across which a load is applied, and (2) they also act as stress concentrators—for an isolated spherical pore, an applied tensile stress is amplified by a factor of 2

A

Porosity

79
Q

It is used to measure the hardness of the ceramic

A

Knoop and vicker technique

80
Q

deformation as a result of exposure to stresses(usually compressive) at elevated temperatures

A

Creep

FUNDAMENTALS OF MATERIAL SCIENCE (5 decks)

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