1. Ceramics
Mixture of metallic and non-metallic elements (clay products).
Traditional: whiteware, tiles, brick, sewer pipe, pottery, and abrasive wheels.
Industrial (fine ceramics): turbine, automotive, aerospace components, heat exchangers, semiconductors, seals, cutting tools.

2. Ceramic Applications Electronic insulators Engine components
Machining tools
Porcelain
Bioceramics for prosthetics

3. Structure of Ceramics
The structure of ceramic crystals is among the most complex of all materials.
Contain various elements.
Covalent bonding (electron sharing), stronger than metals.
Hardness, thermal, and electrical resistance higher than metals.
Finer the grain size, higher strength and toughness.

4. Ceramic Materials Clay (kaolin): silicate of aluminum.
Flint: fine-grained silica.
Feldspar: aluminum silicates, potassium, calcium/sodium.

5. General Properties of Ceramics
Mechanical Properties
Much stronger in compression vs. tension (one magnitude difference)
Sensitive to cracks, impurities, porosity
Lack toughness, ductility, are brittle and strong
static fatigue failure (load over a period of time)- similar to stress-corrosion cracking.
pre-stressing (compressing) increases resistance to breakdown from tensile stress.

6. General Properties of Ceramics
Physical Properties
low specific gravity/density.
low thermal conductivity (porosity – air is poor conductor).
low thermal expansion.
resistance to wear.
Alloying With metallic elements can cause ceramics to conduct

7. Types of Ceramics Oxide Ceramics Alumina Zirconia most widely used
high temperature applications
Electrical, thermal insulation, cutting tools
Zirconia
high toughness/strength
resistance to thermal shock, wear, and corrosion.
low thermal conductivity, friction coefficient.
Engine components

8. Ceramic Knife (Zirconia)
(global.kyocera.com)

9. Other Types of Ceramics
Carbides
tungsten, titanium, and silicon carbide.
Silicon is an abrasive
Grinding wheels, cutting tools
Nitrides
cubic boron nitride, titanium nitride, and silicon nitride.
Grinding and cutting tools, turbine engines, bearings, sand-blast nozzles

10. Other Types of Ceramics (Cont.)
Sialon
silicon nitride and aluminum oxide, yttrium oxide, titanium carbide.
Higher strength and thermal-shock resistance than silicon nitride
Cutting tools
Cermets
ceramics bonded with metallic elements.
cutting tools/high temperature applications.

11. Silica Polymorphic material (different crystal structures) Quartz
Most glasses are 50% silica
Silicates- reaction of silica and oxides of al, mg, fe, etc. (clay, asbestos, mica, and silicate glasses)

12. Glasses Amorphous solid (structure of a liquid)
No specific freezing or melting point
Cooled at a rate too high for crystals to form (supercooled).
All glasses contain at least 50% silica.

13. Glass Applications Containers Windows Cookware Fiber Optics Monitors
Lighting

14. Glass Properties Brittle, hard Resistant to chemicals and corrosion
Low thermal conductivity and expansion.
Dielectric properties.
Reflection, refraction, absorption.
Static Fatigue

15. Glass Ceramics High crystalline structure Stronger than glass
Shaped first and heat treated
devitrification or recrystallization of glass.

16. Graphite Crystalline form of carbon, having a layered structure.
solid lubricant, low friction properties.
brittle in nature.
strength and stiffness increases with temperature.

17. Diamond Hardest substance known Synthetic (or industrial)
lacks impurities which natural diamonds might have.
electrical conductivity is 50 times higher than natural diamonds (heat sinks)

18. Topic Support Kyocera- http://americas.kyocera.com/kicc/index.cfm