ceramics

Question 1

What is a ceramic

Answer 1

inorganic compound, of a metal and 1+= non metal

Question 2

four most common elements in earth’s crust

Answer 2

O2, Silicon, Al, Fe

Question 3

difference between traditional and new ceramics

Answer 3

traditional–clay based (e.g. pottery, bricks)
new–simpler in chemical composition (e.g. oxides, carbides)

Question 4

what distinguishes glass from traditional and new ceramics?

Answer 4

glass is non crystalline (amorphous), ceramics are crystalline

Question 5

3 mechanical properties of ceramic materials

Answer 5

brittle, no ductility, high hardness, low fracture toughness

Question 6

3 physical properties of ceramics

Answer 6

electrical and thermal insulating, medium density (mostly below metals), high melting temperatures, thermal expansion lesser than metals generally

Question 7

thermal expansion in ceramics generally is {lower, higher} than that of metals

Answer 7

lower

Question 8

type of atomic bonding for ceramics

Answer 8

covalent and ionic

Question 9

what does clay consist of, give an example clay

Answer 9

hydrous aluminum silicate
e.g. kaolinite clay
bentonite clay
french green clay

Question 10

what’s glazing, as applied to ceramics

Answer 10

application of oxide surface coating, e.g. using alumina and silica, to a porous ceramic e.g. earthenware, to make produce more impermeable to moisture and more attractive

Question 11

define oxide

Answer 11

compound containing oxygen, e.g. carbon dioxide

Question 12

glazing makes a porous ceramic more {1} to moisture

Answer 12

impermeable

Question 13

meaning of refractory

Answer 13

heat resistant (ceramics, and also to metals that are)

Question 14

2 principal applications of cemented carbides

Answer 14

cutting tool inserts
rock drilling bits
drawing dies
dies for powder metallurgy

Question 15

cemented carbides are ideal for applications where {1} is needed

Answer 15

1: hardness

Question 16

define hardness

Answer 16

resistance to deformation, particularly permanent deformation e.g. scratching, cutting, abrasion
‘materials ability to withstand surface indentation/wear’

Question 17

define toughness

Answer 17

materials ability to absorb energy and plastically deform without fracturing

Question 18

one important application of titanium nitride

Answer 18

prolong tool life via thin coating on cutting tools

Question 19

elements in Sialon

Answer 19

Si, Al, O2, N2

Question 20

what material describes the following:
“An inorganic, non metallic material that cools to a rigid solid without crystallization”

Answer 20

glass

Question 21

primary mineral in glass products

Answer 21

Silica
or SiO2, silicon dioxide

Question 22

what’s the purpose of the additional ingredients added to glass?

Answer 22

increases fluidity in molten glass, during processing
retarding devitrification, tendency to crystalize from glassy state
reduces final products thermal expansion
increase chemical resistant
adds colour
alters index of refraction for optical applications

Question 23

devitrification involves the transformation of …?

Answer 23

glass to polycrystalline state

Question 24

graphite is composed of {1} in form of hexagonal {2} layers. {3} bonding exists between atoms in layers, the parallel layers are bonded by {4} forces, thus leading to highly {ani..} properties

Answer 24

1: carbon
2: crystalline
3: covalent
4: van der waal
anisotropic

Question 25

anisotropic properties meaning

Answer 25

properties vary depending on direction e.g. wood, ice, tourmaline

Question 26

example of isotropic material

Answer 26

diamond, glass, plastic, metals

Question 27

3 advantages of glass ceramics

Answer 27

higher strength than glass
absence of porosity–low thermal expansion
high thermal shock resistance

Question 28

applications of glass ceramics

Answer 28

cooking ware
heat exchanges

Question 29

When glass is heated, it can convert to a {}, face-centered cubic, solid solution. The glass-liquid transition is a gradual and reversible transition in amorphous materials from a hard and {} state to a viscous or {} state as the temperature increases.

Answer 29

crystalline
brittle
rubber-like