The document discusses ceramics as inorganic compounds made from metal and nonmetal elements, highlighting their properties, processing methods, and various applications. Key ceramic materials include silica, alumina, and their complex compounds, with methods for forming such as slip casting and powder pressing. Applications range from construction materials to electrical insulators and cutting tools, showcasing their versatility in high-temperature and structural applications.

1. CERAMICS
Mr.H.P.Varade
Assistant Professor
Sanjivani College of Engineering
Kopargaon,Dist:Ahmednagar

2. Ceramics
An inorganic compound consisting of a metal (or semi-metal) and
one or more nonmetals
 Examples:
Silica - silicon dioxide (SiO2), the main ingredient in most glass
products
Alumina - aluminum oxide (Al2O3), used in various applications
from abrasives to artificial bones
More complex compounds such as hydrous aluminum silicate
(Al2Si2O5(OH)4), the main ingredient in most clay products

3. Ceramic Bonding -

4. Ceramic Crystal Structures-
Oxide structures:
1. Anions are larger than cations.
2. Close packed oxygen in a lattice (usually FCC).
3. Cations fit into interstitial sites among anions.

6. ABX3 Crystal Structures -
6
• Perovskite (calcium titanium
oxide) structure
Ex: complex oxide
Barium Titanate
(BaTiO3)

7. Silicate Ceramics -
• Most common elements on earth are Si & O
• SiO2 (silica) polymorphic forms are quartz, crystobalite, &
tridymite
• The strong Si-O bonds lead to a high melting temperature
(1710ºC) for this material
7
Si4+
O2-
crystobalite

8. 8
Glass Structure -
• Quartz is crystalline
SiO2:
• Basic Unit:
• Glass is noncrystalline (amorphous)
• Fused silica is SiO2 to which no
impurities have been added
• Other common glasses contain
impurity ions such as Na+, Ca2+,
Al3+, and B3+
(soda glass)-
Adapted from Fig. 12.11,
Callister & Rethwisch 8e.
Si0 4 tetrahedron
4-
Si 4+
O 2 -
Si 4+
Na +
O 2 -

9. Properties of Ceramic Materials-

10. Properties of Ceramic Materials-

12. Properties of Ceramic Materials

13. Properties of Ceramic Materials
• High hardness, electrical and thermal insulating,
chemical stability, and high melting temperatures
• Brittle, virtually no ductility - can cause problems
in both processing and performance of ceramic
products

14. Processing of Ceramics-
1.Slip Casting-
• A suspension of ceramic powders in water, called a slip, is poured into a
porous plaster of paris mold, so that water from the mix is absorbed into
the plaster to form a firm layer of clay at the mold surface .
•The slip composition is 25% to 40% water

15. Figure - Sequence of steps in drain casting, a form of slip casting:
(1) slip is poured into mold cavity,
(2) water is absorbed into plaster mold to form a firm layer,
(3) excess slip is poured out, and
(4) part is removed from mold and trimmed

16. • Drying: as water is removed - interparticle spacings decrease
– shrinkage .
2.Drying and Firing -
Drying too fast causes sample to warp or crack due to non-uniform shrinkage
wet body partially dry completely dry
• Firing:
-- heat treatment between
900-1400ºC
-- vitrification: liquid glass forms
from clay and flux – flows
between SiO2 particles. (Flux
lowers melting temperature).

17. • Mill (grind) and screen constituents: desired particle size
• Dry and fire the formed piece
ram
billet
container
container
force
die holder
die
A o
A
d
extrusion
3. Hydroplastic forming:-

18. 4. Powder Pressing:
used for both clay and non-clay compositions.
• Powder (plus binder) compacted by pressure in a mold
-- Uniaxial compression - compacted in single direction
-- Isostatic (hydrostatic) compression - pressure applied by
fluid - powder in rubber envelope
-- Hot pressing - pressure + heat

19. Ceramic Products
• Clay construction products - bricks, clay pipe, and building tile ,cement
concrete
• Refractory ceramics - ceramics capable of high temperature applications
such as furnace walls, crucibles, and molds
• White ware products - stoneware, fine china, porcelain, and other
tableware, based on mixtures of clay and other minerals
• Glass - bottles, glasses, lenses, window pane, and light bulbs
• Glass fibers - thermal insulating wool, reinforced plastics (fiberglass), and
fiber optics communications lines
• Abrasives - aluminum oxide and silicon carbide
• Cutting tool materials - tungsten carbide, aluminum oxide, and cubic
boron nitride

20. • Ceramic insulators - applications include electrical transmission
components, spark plugs, and microelectronic chip substrates
• Magnetic ceramics – example: computer memories
• Nuclear fuels based on uranium oxide (UO2)
• Bioceramics - artificial teeth and bones

21. Ceramic Materials- Applications
Clay – Shaped, dried, and fired
inorganic material
Examples: Brick, tile, sewer pipe,
chimney flue, china, porcelain, etc.
Refractory – Designed to provide
acceptable mechanical or chemical
properties while at high temperatures
Example: Space shuttle all-silica
insulating tiles

22. Applications of Ceramic Materials
Rectifiers – Allow current to
flow in one direction
Heating elements for furnaces
Electrical
Resistors – Create desired voltage drops
and limit current
Thermistors – Application of
heat regulates current flow

23. • Alumina(Al2O3) is used as insulators in spark plug and
electronic packaging, rocket nozzles etc.
• Tungsten carbide and Titanium carbide along with metal
binders like Ni, Co, Cr, Mo are known as cermets which are
used as cutting tool materials.
• Tungsten carbide is used as an abrasive material for grinding
and polishing operations

24. Typical Applications of Ceramics

25. THANK YOU