2. Outline
Ceramics
Nature and Structure
Ceramic Products
Design of a Ceramic
Processing of a Ceramics
3. Ceramics
Ceramics, by definition, comprise inorganic, non-
metallic, non-water-soluble compounds that show
ionic contributions in their chemical bonds.
HIGH
hardness, heat resistance, corrosion resistance
LOW
electrical and thermal conductivity, ductility,
fracture toughness
4. Ceramics
Hard, brittle, high melting point materials
with low electrical and thermal
conductivity, low thermal expansion, good
chemical and thermal stability, good creep
resistance, high elastic modulus and high
compresive strengths.
5. Nature and Structure
Compounds of metallic
and nonmetallic elements
(in forms of oxides,
carbides and nitrides)
Exist in a wide variety of
compositions and forms
Most have crystalline
structures (strong ionic or
covalent bonds)
6. Nature and Structure
Absence of free electrons
makes ceramics poor
electrical conductors.
High melting
temperatures.
Noncrystalline structure
is also possible in solid
ceramics. This
amorphous condition is
called glassy state.
8. Ceramic Products
Clay and Whiteware
Products
Ex: brick, roof and
structural tiles,
drainage and sewer
pipe, sanitory ware,
dinnerware, china,
decorative floor and
wall tile, pottery and
other artware.
9. Ceramic Products
Clay and Whiteware
Products
Ex: brick, roof and
structural tiles,
drainage and sewer
pipe, sanitory ware,
dinnerware, china,
decorative floor and
wall tile, pottery and
other artware.
10. Ceramic Products
Refractory Materials
are ceramics that have
been designed to provide
acceptable mechanical
and chemical properties
at high temperatures.
Ex: bricks and shaped
products, bulk form for
coating, insulating
ceramic fibers.
12. Ceramic Products
Glasses
are amorphous solid form of
ceramics
Ex: window glass,
containers, light bulbs, TV
and computer display tubes,
fiberglass insulation, glass
cookware, fiberoptic
communication.
Glass Ceramics
recrystallite or vitrificated
glass
13. Ceramic Products
Cermets
are combination of
metals and ceramics,
bonded together by
the procedures of
powder metallurgy.
Structural Ceramics
mechanical
application
14. Advanced Ceramics
This new class of ceramic materials will
have the high-temperature stability,
corrosion resistance, and toughness
necessary for a wide range of applications.
They also can provide substantial energy,
environmental, and economical benefits,
including lower maintenance, higher
efficiency, and decreased operating costs.
15. Advanced Ceramics
Advanced ceramics can be used in the chemicals,
aluminum, metal casting, forest products, glass,
petroleum refining, and steel industries, to name a
few. Uses for advanced ceramic components
include: diesel engine exhaust valves; IR burners;
heat exchanger tubes; hot gas filters; gas turbine
combustor liners and shrouds; and combustion
components for small stationary gas turbines[10].
16.
17. Design of a Ceramic
Because of their properties - their inherent
brittleness; inability to yield, change shape, or
plastically deform; sensitivity to defects;
tendency to break at any point of high stress
concentration; microstructures, which possess
flaws that can cause failure without being
detected beforehand-ceramics require a design
model that calls for greater degrees of accuracy in
the design and manufacture of ceramic parts.
18. Design of a Ceramic
Anyone who has experienced breaking a piece of
glass will know about the sensitivity of brittle
materials to defects. A slight scratch on the
surface of the glass and a small bending force to
produce a tensile stress are all that is needed to
break a relatively thick piece of glass. This flaw
sensitivity means that a ceramic cannot be
considered as having only one strength but rather,
a distribution of strengths, depending on the flaws
in the material that were added during processing,
final machining, or testing, or while in service.
19. Processing of a Ceramic
Five main steps in the manual
production process:
1. Preparation , including Clay
Fermentation, Clay Kneading
2. Molding
20. Processing of a Ceramic
3. Making up that can be separated
into 3 kinds: Scratching, Fretwork,
and Molding with liquid clay.
4. Drying: Natural drying takes 15-30
days in Summer and more than 30
days in Rainy Season.
21. Processing of a Ceramic
5. Firing: It can be separated into 3
levels of fire: Low Fire (200-300ºC),
Middle Fire (300-900ºC), High Fire
(900-1,300ºC). After the pottery has
been sufficiently air-dried, it will be
fired in a kiln using the traditional
firewood method.
22. Processing of a Ceramic
A three-step firing method is applied
starting with a low firing of 400ºC for
12 hours, followed by a 900ºC
setting for another six hours, and
then a 1000ºC setting for another six
hours to achieve an antique finish. If
the buyer requires a dark red finish,
the final stage of firing will be
increased to 1280 ºC.
23. Processing of a Ceramic
New processes and advances in forming
and manufacturing techniques introduced
in recent years have led to the development
of advanced ceramics with the properties
and application potential to solve what
were once regarded as seemingly
impossible technical and engineering
challenges.
24. Processing of a Ceramic
compaction of powder
firing - applying heat (below melting
temperature) to achieve bonding of
particles, (reducing pore size) called
densification
sintering - removal of pores and addition of
strong bonding forces that provides added
strength, but reduced size
25. Processing of a Ceramic
The process by which progression was
measured took quite a long time to evolve.
In the beginning, the production was done
completely by hand. Today, that is no
longer so.
