PRACTICE QUIZ

Question 1

Mechanical Properties, thermal properties

Answer 1

hardness,
brittleness, and high melting temperatures.

Question 2

Ceramic pieces normally cannot be
fabricated using conventional metal forming
techniques

Answer 2

TRUE

Question 3

are a familiar group of ceramics

Answer 3

glasses

Question 4

What are the
applications of glasses

Answer 4

containers, lenses, and fiberglass

Question 5

they are
noncrystalline silicates containing other oxides, notably
CaO, Na2O, K2O, and Al2O3, which influence the its
properties.

Answer 5

glasses

Question 6

consists of
approximately 70 wt% SiO2, the balance being mainly
Na2O (soda) and CaO (lime).

Answer 6

soda–lime glass

Question 7

two prime
assets of glasses

Answer 7

optical transparency
and the relative ease with which they may be
fabricated.

Question 8

Most inorganic glasses can be made to
transform from a noncrystalline state to one that is
crystalline by the proper high-temperature heat
treatment.

Answer 8

Crystallization

Question 9

The product of crystallization is a fine grained polycrystalline material
that is often called a

Answer 9

glass-ceramic.

Question 10

the formation of
these small glass-ceramic grains is, in a sense, a
phase transformation, which involves

Answer 10

nucleation and
growth stages.

Question 11

is
often added to the glass to promote crystallization

Answer 11

nucleating agent

Question 12

exmaple of nucleating agent

Answer 12

titanium dioxide

Question 13

Glass-ceramic materials have been designed to have relatively high mechanical strengths

Answer 13

true

Question 14

Glass-ceramic materials have been designed to have high coefficients of thermal expansion (to avoid thermal
shock);

Answer 14

FALSE

Question 15

Glass-ceramic materials have been designed to have relatively high temperature capabilities;
*good dielectric properties (for electronic packaging
applications);

Answer 15

TRUE

Question 16

Glass-ceramic materials have been designed to have good biological compatibility

Answer 16

TRUE

Question 17

Some glass-ceramics may be made optically

Answer 17

transparent;
others are opaque.

Question 18

the most attractive attribute of GLASS CERAMICS

Answer 18

ease with which they may be
fabricated

Question 19

used conveniently in the mass production of nearly pore-free
ware.

Answer 19

conventional glass-forming techniques

Question 20

Glass-ceramics are manufactured
commercially under the trade names of

Answer 20

Pyrocem
CorningWare
Cercor
Vision

Question 21

most common uses for glass ceramics
are ovenware, tableware, oven
windows, and range tops

Answer 21

ovenware,
tableware,
oven
windows, and
range tops

Question 22

Why are glass ceramics used in thermal environment usage

Answer 22

strength
excellent resistance to thermal shock
serve as electrical insulators
substrates for printed circuit boards
architectural cladding
heat exchangers and
regenerators

Question 23

most widely used ceramic raw
materials

Answer 23

Clay

Question 24

inexpensive ingredient,
found naturally in great abundance

Answer 24

clay

Question 25

is used as mined without any upgrading of quality

Answer 25

clay

Question 26

its popularity lies in the ease with which they may be formed

Answer 26

clay

Question 27

when mixed in the proper proportions, clay and water form

Answer 27

plastic mass

Question 28

is very amenable to shaping.

Answer 28

plastic mass

Question 29

Most of the clay-based products fall within two broad classifications

Answer 29

structural clay products and the whitewares

Question 30

include building bricks, tiles, and sewer pipes—applications in which structural integrity is important.

Answer 30

Structural clay products

Question 31

become white after the high- temperature firing. Included in this group are porcelain, pottery, tableware, china, and plumbing fixtures (sanitary ware).

Answer 31

Whiteware ceramics

Question 32

Another important class of ceramics that are used in large tonnages

Answer 32

refractory ceramics.

Question 33

salient properties of refractory ceramics

Answer 33

withstand high temperatures without melting or decomposing and the capacity to remain unreactive and inert when exposed to severe environments.

Question 34

most common marketed form of refactory materails

Answer 34

bricks

Question 35

The performance of a refractory ceramic depends to a large degree on its composition. On this basis, there are several classifications

Answer 35

1. Fireclay ref. 2. Silica Ref. 3. Basic Ref. 4. Special ref.

Question 36

The primary ingredients for the fireclay refractories are

Answer 36

high-purity fireclays, alumina and silica mixtures usually containing between 25 and 45 wt% alumina.

Question 37

During refractory service use, the presence of a small amount of a liquid phase is not allowable so does compromising mechanical integrity.

Answer 37

false

Question 38

at this temperature, the fraction of liquid phase present will depend on refractory composition

Answer 38

above 1587 degree celscius

Question 39

are used principally in furnace construction, to confine hot atmospheres, and to thermally insulate structural members from excessive temperatures.

Answer 39

fireclay bricks

Question 40

strength is not ordinarily an important consideration in this type of brick

Answer 40

fireclay

Question 41

Its prime ingredient is silica and it is sometimes termed as acid refractories

Answer 41

Silica Ref.

Question 42

These materials, well known for their high-temperature load- bearing capacity, are commonly used in the arched roofs of steel- and glass-making furnaces

Answer 42

Silica Ref.

Question 43

slags that are rich in silica and is often used as containment vessels for them.

Answer 43

acid slags

Question 44

Since they are readily attacked by slags composed of a high proportion of ________, and _________contact with these oxide materials should be avoided.

Answer 44

CaO and/or MgO (basic slugs)

Question 45

refractories that are rich in periclase, or magnesia (MgO), and may also contain calcium, chromium and iron compounds, are termed

Answer 45

Basic ref.

Question 46

The presence of this compound is deleterious to Basec ref's high- temperature performance

Answer 46

silica

Question 47

are especially resistant to attack by slags containing high concentrations of MgO and CaO and find extensive use in some steel- making open hearth furnaces

Answer 47

Basic refractories

Question 48

are relatively high-purity oxide materials, many of which may be produced with very little porosity.

Answer 48

Special Refractories

Question 49

Included in this group are alumina, silica, magnesia, beryllia (BeO), zirconia (ZrO2), and mullite (3Al2O3–2SiO2)

Answer 49

speical ref.

Question 50

has been used for electrical resistance heating elements, as a crucible material, and in internal furnace components.

Answer 50

Silicon carbide (SiC)

Question 51

are very refractory, but find limited application because they are susceptible to oxidation at temperatures in excess of about 800°C (1470°F).

Answer 51

Carbon and graphite

Question 52

Expected to be relatively expensive

Answer 52

spe. ref.

Question 53

are used to wear, grind, or cut away other material, which necessarily is softer.

Answer 53

abrasive ceramics

Question 54

he prime requisite for this group of materials is hardness or wear resistance; in addition, a high degree of toughness

Answer 54

abrasive ceramics

Question 55

may be produced from abrasive frictional forces, so some refractoriness is also desirable.

Answer 55

high temperatures

Question 56

both natural and synthetic, are utilized as abrasives

Answer 56

diamond

Question 57

are used in several forms— bonded to grinding wheels, as coated abrasives, and as loose grains

Answer 57

abrasives

Question 58

the abrasive particles are bonded to a wheel by means of a glassy ceramic or an organic resin

Answer 58

bonded to form grinding wheels

Question 59

The surface structure should contain some porosity; a continual flow of air currents or liquid coolants within the pores that surround the refractory grains prevents excessive heating

Answer 59

true

Question 60

are those in which an abrasive powder is coated on some type of paper or cloth material

Answer 60

Coated abrasives

Question 61

is probably the most familiar example of coated abrasive

Answer 61

sandpaper

Question 62

are all frequently ground and polished using this form of abrasive

Answer 62

woods, metal, cermaics and plastics

Question 63

are all frequently ground and polished using this form of abrasive

Answer 63

loose abrasive grains

Question 64

delivered in some type of oil- or water-based vehicle

Answer 64

loose abrasive grains

Question 65

Several familiar ceramic materials are classified as inorganic

Answer 65

cements

Question 66

cement, plaster of paris, and lime, which, as a group, are produced in extremely large quantities.

Answer 66

cements

Question 67

materials act as a bonding phase that chemically binds particulate aggregates into a single cohesive structure.

Answer 67

cements

Question 68

glassy bonding phase that forms when clay products and some refractory bricks are fired. One important difference, however, is that the cementitious bond develops at room temperature

Answer 68

true

Question 69

consumed in the largest tonnages

Answer 69

Portland cement