8.3Composition of Ceramics and Its Uses
Ceramics are inorganic, non-metallic solid materials that are shaped and hardened by heating at very high temperatures. They possess unique physical and chemical properties such as high thermal resistance, hardness, and electrical insulation.
Learning Objectives
- Describe briefly with examples of ceramics, their composition, properties, and uses.
- Explain the uses of ceramics in daily life, including medicine, transportation, and energy production.
Basic Properties and Classification of Ceramics
Strong atomic bonding gives ceramics their six shared properties, while their composition divides them into traditional and advanced ceramics.
Traditional Ceramics
Made from natural clay such as kaolin, \(\text{Al}_2\text{O}_3\cdot 2\text{SiO}_2\cdot 2\text{H}_2\text{O}\).
Clay is mixed with water, shaped, then heated at a very high temperature.
Uses: bricks, pottery, crockery such as bowls.
Advanced Ceramics
Made from inorganic compounds such as oxides, carbides, and nitrides.
Higher resistance to heat and abrasion, more chemically inert, and possess superconductivity properties.
Uses: cutting discs, brake discs, tungsten carbide rings (hard and abrasion-resistant), jet engine components, medical implants, MRI machines, power station insulators.
Six Shared Basic Properties
Brief Explanation
Understand the composition, bonding and classification of ceramics.
Examples of Ceramic Compounds
- Aluminium oxide, \(\text{Al}_2\text{O}_3\)
- Titanium carbide, \(\text{TiC}\)
- Silicon carbide, \(\text{SiC}\)
Atomic Bonding and Properties
Atoms in ceramics are bonded by strong covalent bonds and ionic bonds in an indefinite arrangement. Electrons cannot move freely, so ceramics are electrical and heat insulators.
| Property | Explanation |
|---|---|
| High melting point, hardness, compression resistance | Strong covalent and ionic bonds between atoms. |
| Brittleness and weak towards stretching | Atoms cannot slide over each other when force is applied; the energy breaks the bonds between atoms. |
| Electrical and heat insulation | Electrons cannot move freely to conduct electricity or heat. |
Traditional Ceramics
Made from clay such as kaolin, \(\text{Al}_2\text{O}_3\cdot 2\text{SiO}_2\cdot 2\text{H}_2\text{O}\). Clay is mixed with water to produce a soft, mouldable mixture, then heated at a very high temperature. Used for bricks, pottery, and crockery.
Advanced Ceramics
Made from inorganic compounds such as oxides, carbides, and nitrides. They have higher resistance to heat and abrasion, are more chemically inert, and possess superconductivity properties.
| Application Area | Specific Use | Ceramic Material |
|---|---|---|
| Medicine | Dental implants | Zirconia ceramic |
| Medicine | Knee bone replacements | Alumina ceramic |
| Medicine | MRI machines | Ceramics with superconductivity properties |
| Transportation | Engine components in jet planes | Ceramics |
| Energy Production | Electrical insulators in high-voltage areas such as power stations | Ceramics |
Try to Answer First
Answer mentally, then check the explanation.
What is the raw material used to produce traditional ceramics, and what is its chemical formula?
Why are ceramics brittle and break easily when a force is applied?
State two medical applications of ceramics and the specific ceramic material used for each.
Common Mistakes
Avoid these errors when explaining ceramics.
Concept Misunderstandings
Compare each misconception with the correct fact.
Advanced ceramics are just traditional clay ceramics coated with metals.
Advanced ceramics are made directly from inorganic compounds such as oxides, carbides, and nitrides, not from clay.
All ceramics are identical in heat resistance and abrasion resistance.
Advanced ceramics have significantly higher resistance to heat and abrasion compared to traditional ceramics.
Ceramics cannot be used in electronic or medical technology because they are too brittle.
Ceramics possess specific properties such as superconductivity and biocompatibility, allowing them to be used in MRI machines, dental implants, and artificial knee bones.
Summary
Key facts to remember.
- Ceramic: Inorganic and non-metallic solid shaped and hardened by heating at high temperatures.
- Basic properties: Hard and strong, brittle, chemically inert, heat insulator, electrical insulator, and high thermal resistance.
- Bonding: Strong covalent and ionic bonds in an indefinite arrangement; no free-moving electrons.
- Traditional ceramics: Made from kaolin clay \(\text{Al}_2\text{O}_3\cdot 2\text{SiO}_2\cdot 2\text{H}_2\text{O}\); used for bricks, pottery, and crockery.
- Advanced ceramics: Made from oxides, carbides, and nitrides; used for cutting discs, brake discs, tungsten carbide rings, jet engine components, dental implants, knee bone replacements, MRI machines, and power station insulators.
Short Activity
Complete all parts before checking your score.
A. Objective Quiz
Which of the following compounds is the primary clay component used in making traditional ceramics?
Why are ceramics classified as good electrical insulators?
B. Fill in the Blanks
Advanced ceramics such as silicon carbide are used to make brake discs because they have high resistance to heat and can withstand ______.
In medicine, ______ ceramic is specifically used to make knee bone replacements.
C. Match the Ceramic Application with Its Function
Drag each ceramic on desktop. On mobile, tap a ceramic and then tap the matching box.
Ceramic / Application
Zirconia ceramic Silicon carbide MRI machine component High-voltage power station insulatorFunction / Specific Material
Keywords
Tap or hover over a term to read its meaning.
