Ceramics are manufactured by shaping and heating non-metallic, inorganic materials.
The process typically includes powder preparation, shaping, drying, and firing at high temperatures.
High heat gives ceramics their hardness, strength, and heat resistance.
Ceramic manufacturing is used to produce items like tiles, bricks, and advanced engineering components.

MANUFACTURING OF CERAMICS

Ceramics are inorganic, non-metallic materials made by shaping and firing raw materials at high temperatures. Ceramic manufacturing involves a series of controlled steps to achieve desired shape, strength, and properties.

1. Raw Materials Used in Ceramics

Ceramic raw materials are generally naturally occurring minerals.

Main Raw Materials

Clay – provides plasticity (e.g., kaolin)
Silica (SiO₂) – provides strength and thermal stability
Feldspar – acts as a flux (lowers melting temperature)
Alumina (Al₂O₃) – increases hardness and refractoriness
Magnesia, zirconia – for advanced ceramics

2. Steps in Ceramic Manufacturing Process

Step 1: Raw Material Preparation

Raw materials are:

Mined
Crushed
Ground to fine powder

Objectives:

Uniform particle size
Removal of impurities
Improved sintering behavior

Processes used:

Ball milling
Crushing and grinding
Screening and magnetic separation

Step 2: Batching and Mixing

Prepared raw materials are weighed in correct proportions and mixed.

Purpose:

Achieve uniform composition
Ensure consistent properties

Methods:

Dry mixing
Wet mixing (slurry preparation)

Step 3: Forming (Shaping)

The mixed material is shaped into desired forms.

Common Forming Methods

a) Dry Pressing

Powder pressed in steel dies
High pressure applied

Used for: Tiles, electrical insulators

b) Slip Casting

Ceramic slurry poured into plaster molds
Mold absorbs water and forms solid layer

Used for: Complex shapes, sanitary ware

c) Extrusion

Plastic clay forced through die

Used for: Bricks, pipes, tiles

d) Injection Molding (Advanced Ceramics)

Ceramic powder mixed with polymer binder
Injected into molds

Used for: Precision ceramic parts

Step 4: Drying

Formed ceramic bodies contain moisture and must be dried.

Purpose:

Remove free water
Prevent cracking during firing

Drying methods:

Air drying
Controlled chamber drying

Step 5: Firing (Sintering)

Dried ceramic pieces are heated in a kiln at high temperatures.

Temperature range:

900°C – 1800°C (depending on ceramic type)

Processes during firing:

Removal of bound water
Burning of organic materials
Particle bonding (sintering)
Increase in strength and hardness

Types of kilns:

Periodic kiln
Tunnel kiln
Shuttle kiln

Step 6: Glazing (Optional)

Glazing involves applying a glassy coating before or after firing.

Purpose:

Improve surface finish
Increase water resistance
Enhance appearance

Types of glazing:

Raw glazing
Frit glazing

Step 7: Finishing and Inspection

Grinding or polishing
Dimensional checking
Strength and quality testing

3. Manufacturing of Advanced Ceramics

Advanced ceramics require high purity powders and precise control.

Steps include:

Chemical powder synthesis
Isostatic pressing
Hot pressing or hot isostatic pressing
Precision machining

Examples:

Alumina ceramics
Silicon carbide
Zirconia ceramics

4. Properties Achieved After Manufacturing

High hardness
High compressive strength
Heat resistance
Wear resistance
Electrical insulation

5. Applications of Manufactured Ceramics

Traditional Ceramics

Bricks
Tiles
Pottery
Sanitary ware

Advanced Ceramics

Cutting tools
Engine components
Biomedical implants
Electronic substrates

6. Advantages of Ceramic Manufacturing

Uses abundant natural materials
Excellent thermal stability
Long service life
Chemical resistance

7. Limitations

Brittle nature
High firing energy cost
Difficult machining after firing

8. Flow Chart of Ceramic Manufacturing

Raw materials → Crushing & grinding → Mixing → Forming → Drying → Firing → Glazing → Finishing

9. Conclusion

Ceramic manufacturing is a multi-step process that transforms raw minerals into strong, durable, and heat-resistant products. Control at each stage is essential to prevent defects and achieve desired properties.