ENGINEERING METALLURGY

1. CERAMICS
Inorganic solid

2. Introduction
• It’s a man made non metallic and inorganic solid

3. Traditional products
• Bricks
• Cook wares
• Cements
• Concretes
• Tiles
• potteries

4. Traditional products

5. Other engineering applications
Used as
• tool for grinding and Cutting
• Bearings
• And many in electrical and electronics fields.

6. Other engineering applications

7. Characteristics of ceramics
• Used in high temperature places
• Its strong, hard and brittle
• High melting point
• Good thermal and electrical insulators
• Resistant to oxidation and corrosion
• Having high compressive strength but are weak in tension

8. Engineering ceramics
• Its specially for engineering applications
• They are basically oxides, carbides, sulphides
and nitrides of metal.

9. Characteristics of engineering ceramics
• High resistance to abrasion and wear
• High strength at high temperature
• Good chemical stability
• Good electrical insulation characteristics.

10. Important engineering ceramics
• Alumina (Al2O3)
• Silicon Carbide (SiC)
• Silicon Nitride (Si3N4)
• Partially stabilized Zirconia
• Sialons

11. Alumina (aluminium oxide)
• Its produced from bauxite
• It’s a old engineering ceramic

12. BAUXITE ORE

13. Properties of Alumina
• Excellent hardness, wear resistance
• They are more stiffer than steel
• More stronger in compression than hardened steel
• Very good environmental resistance (CORROSION)
• Alumina mixed with ceramics to get high tensile
and toughness properties.

14. Applications of alumina
Used in
• Spark plug insulators
• Electronic circuits
• Rocket nozzles
• Electrical and electronics devices
• In nuclear power plant
• bearings

15. Silicon carbide (sic)
• It’s a semi conducting ceramic material
• Types
Alpha Sic
Beta Sic

16. Properties of Sic
• High tensile strength
• High stiffness , hardness
• Better dimensional stability
• Good wear resistant
• Good corrosion resistant.

17. Applications of Sic
Used
• As a abrasives for grinding wheel
• As a coating material
• As a refractory tubes
• In nuclear reactor
• In bearings
• And in very high temperature places

18. Silicon nitrate (Si3n4)
• It’s a use full ceramics in chemical industries

19. Properties of silicon nitrides
• Resistant to strong acids
• Resistance to thermal
• Low density and low weight
• Low thermal expansion
• More stiffer

20. Applications of silicon nitrides
Used in
• Cutting tool materials
• Turbine parts
• Pump parts
• High temperature engineering components

21. Partially stabilized zirconia (PSZ)
• It’s a zirconium oxide
• Blended and sintered with others like
magnesium oxide, calcium oxide

22. Properties of PSZ
• High tensile strength
• Low thermal conductivity

23. Applications of PSZ
Used in
• As a blade in jet engine
• As a joint
• In furnace portions
• Internal combustion engine parts

24. Sialons
• They are Si – Al – O – N
• They are formed when Aluminium and oxygen
partially substitute for silicon and nitrogen in
silicon nitride

25. Properties of sialons
• High tough and strength
• Good mechanical properties
• Light weight
• Low co-efficient of thermal expansion

26. Applications of sialons
Used in
• Cutting material
• Nozzles
• Welding shields
• Radiant heater tubes
• impellers

27. COMPOSITES
TO GET A REQUIRE PROPERTIES
IN METALS

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29. COMPOSITES
• Two or more materials added to get require qualities in
a material.
• The weakness of one metal rectified by the strength of
second metal
• Example
Aerospace components
• That should have low weight , stiffness, impact and
corrosion resistance, good abrasive properties.

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31. Particle re-inforced (FIBER)
composites
• Its consist of particles of one material dispersed in a matrix of
a second material
• The fine dispersion particle posses
good strength in composites.
• The size, distribution and orientation of particles defines the
strength of the composite.
• Types
1. dispersion strengthened composites
2. Large particle composites

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33. 1.Dispersion strengthened composites
• The particles are smaller and having diameter 0.01 –
0.1 microns and volume concentration 1 – 15 % of fiber
• This method is similar to that for precipitation hardening.
• Due to this , the composites have good yield and
tensile strength. And the plastic deformation is
restricted.

34. 2. Large particle composites
• The particles diameter greater than 1 micrometer and volume
concentration are greater than 25 %
• Here the load on this composite is shared by both matrix and
particles.
• It posses good strength
• Tungsten carbide or Titanium carbide embedded in a metal
matrix of cobalt or nickel.
• These composites used as a cutting tool

35. FIBRE REINFORCED COMPOSITES
• Here the dispersed phase is in the form of fibers.
• These fibre reinforced composites having improved
strength, fatigue resistant, stiffness and strength-to-
weight ratio

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40. Advantages
• Good mechanical properties – high toughness, elastic
modulus, good fatigue properties
• Used in light weight needed places
• We can fabricate to any shape and size
• Good aero- space applications than conventional
materials.
• Good corrosion resistance
• Not much sensitive to thermal shocks and
temperature changes.

41. Limitations
• High cost than many conventional materials
• Polymeric materials cannot be used for high
temperature applications.

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