Characteristics of Ceramic Materials

1
Chapter 12

• Characteristics of Ceramic Materials

2
Objectives

• Divisions of ceramic clay and glass.
• Ceramic stock including synthetic materials such
  as high temperature carbide and natural materials
  such as soapstone and clay.
• Traditional ceramics.
• Industrial ceramics.

3
Background

• Ceramic products are made of clay, an inorganic,
  nonmetallic solid material that is derived from
  naturally decomposed granite.
• Ceramic products such as brick, pottery, and art
  ware have been made from sand and clay since the
  Iron Age and Bronze Age.
• Advanced ceramics companies are manufacturing
  high temperature cutting tools, artificial
  joints, and much more.
• In the telecommunications industry, glass fiber
  cables, about the thickness of a human hair carry
  more than 50,000 telephone conversations.
  Conventional copper wires are able to carry 24
  simultaneous telephone conversations.

4
Unique Characteristics of Ceramics

• The advantages of ceramics are high melting
  temperatures, high hardness, high compressive
  strength, and low electrical and thermal
  conductivity. Ceramics are able to survive
  corrosive gases, molten metals, and acids.
• The disadvantages are low impact strength and a
  high degree of brittleness.
• Uses include diesel engine exhaust valves and
  heat exchange tubes, hot gas filters, and gas
  turbine combustion chamber liners.

5
Ceramics in Space

• The heat resistant tiles on the underside of the
  shuttle are part of the thermal protection system
  (TPS) that protect the shuttle as temperatures
  reach 3000 0 F as the orbiter returns to earth.
• The quality of materials are greatly improved
  when produced in the weightless environment of
  space.

6
Other Applications of Ceramics

• Ceramics are used for gun liners, ceramic armor,
  and ammunition parts.
• The NATO C-130 aircraft are equipped with fiber
  and glass ceramic cockpit armor.
• Doctors are experiencing success with ceramics in
  hip and knee joint replacements. Ceramics are
  also used of heart valves, and dental implants.
• Containment booms suing ceramic material are
  being used to surround oil spills.
• Ceramics are also used for floor tiles, brick,
  gypsum board, sewer pipes and glass.

7
Ceramics

• Traditional Ceramics include clay and glass
  products - structural clay products, white ware,
  refractories, glass, abrasives, and cement.
• Advanced Ceramics include 4 major industry
  segments structural, electrical, coatings,
  chemical and environmental ceramics.
• Companies are now able to combine metals and
  ceramics to make cermet (ceramic/metal composite)
  cutting tool inserts. They are made either from
  aluminum oxide or titanium carbide to create a
  very hard shock resistant cutting surface.

8
The Nature of Industrial Stock

• Long before the pyramids, craftsmen combined
  local clay and water, shaped the plastic material
  by hand to make pottery to store food and water,
  and then permanently removed the water using
  direct fire or heated furnaces.
• Egyptian glass beads were discovered that date
  back to about 2500 BC. The basic raw material for
  glass is silica. Soda-lime glass is used
  extensively for light bulbs, bottles, and windows.

9
Summary

• Ceramic products are made of clay, an inorganic,
  nonmetallic solid material that is derived from
  naturally decomposed granite.
• In the telecommunications industry, glass fiber
  cables, about the thickness of a human hair carry
  more than 50,000 telephone conversations.
• The advantages of ceramics are high melting
  temperatures, high hardness, high compressive
  strength, and low electrical and thermal
  conductivity. Ceramics are able to survive
  corrosive gases, molten metals, and acids.
• The heat resistant tiles on the underside of the
  shuttle are part of the thermal protection system
  (TPS) that protect the shuttle as temperatures
  reach 3000 0 F as the orbiter returns to earth.
• Doctors are experiencing success with ceramics in
  hip and knee joint replacements. Ceramics are
  also used of heart valves, and dental implants.
• Companies are now able to combine metals and
  ceramics to make cermet (ceramic/metal composite)
  cutting tool inserts.

10
Home Work

• 1. What is the advantage of glass fiber cables?
• 2. What are the advantages of ceramics?
• 3. What are cermets?