Carbon fibers are very strong and lightweight materials composed of carbon atoms bonded together in thin filaments. They have a high strength-to-weight ratio compared to steel or plastic. Carbon fibers are manufactured through a process of spinning a precursor material like polyacrylonitrile, stabilizing it, carbonizing it at a very high temperature, and applying surface treatment and sizing. They have properties including high tensile strength, electrical and thermal conductivity, resistance to corrosion, and stability at high temperatures. Carbon fibers are used to reinforce composites in applications like aerospace, civil engineering, sports equipment, and automotive parts due to their mechanical properties.

1. CARBON FIBERS

2. CONTENTS :
•Introduction
•Types
•Structure
•Manufacturing
•Properties
•Applications

3. INTRODUCTION
• Carbon fiber is composed of carbon atoms bonded
together to form a long chain.
• A material consisting of thin, strong filaments of
carbon, used as a strengthening material, specifically in
resins and ceramics.
• Very strong and lightweight.
• Can be thinner than hair.
• Gains strength when twisted together like yarn.
• Strength to weight ratio much higher than either steel or
plastic.
• Each strand of carbon fiber is 5-10ɥm in diameter.

4. • Carbon fibers were developed in the 1950s by
heating strands of rayon until they carbonized.
•In the early 1960s, a process was developed
using polyacrylonitrile as a raw material.
• During the 1970s, experimental work to find
alternative raw materials led to the introduction
of carbon fibers made from a petroleum pitch
derived from oil processing.

6. TYPES OF CARBON FIBERS
Based on carbon fiber properties:
• Ultra-high-modulus, type UHM (modulus •
>450Gpa)
• High-modulus, type HM (modulus between • 350-
450Gpa)
• Intermediate-modulus, type IM (modulus •
between 200-350Gpa)
• Low modulus and high-tensile, type HT (modulus
• < 100Gpa, tensile strength > 3.0Gpa)
• Super high-tensile, type SHT (tensile strength • >
4.5Gpa)

7. Based on precursor fiber materials:
•PAN-based carbon fibers
•Pitch-based carbon fibers
•Mesophase pitch-based carbon fibers
•Isotropic pitch-based carbon fibers
•Rayon-based carbon fibers
•Gas-phase-grown carbon fibers

8. STRUCTURE
•The atomic structure of the carbon fiber is similar
to the graphite one, which is composed by flat
sheets of carbon atoms (Graphene) placed
following a regular hexagonal pattern. The
difference between each of them is the way that
the sheets are linked. The inter-molecular
strengths between each sheets are relatively
smaller(Van Der Waals), giving the graphite its
soft and brittle properties.

9. Structural model of carbon fiber

11. MANUFACTURING OF CARBON FIBERS
• Each carbon filament is produced from a polymer such
as polyacrylonitrile (PAN), rayon, or petroleum pitch,
known as precursor.
• Most carbon fibers (about 90%) are made from the
polyacrylonitrile (PAN) process.
• A small amount (about 10%) are manufactured from
rayon or the petroleum pitch process.
• In general there are 5 stages of carbon fiber
manufacturing.

12. Stages of carbon fiber manufacturing
• Spinning: Precursor is mixed with other ingredients
and spun into fibers, which are then washed and
stretched.
• Stabilization: The fibers undergo chemical alteration
to stabilize bonding.
• Carbonization: Stabilized fibers are heated to very
high temperature forming tightly bonded carbon
crystals

13. • Surface Treatment: ​The surface of the fibers is
oxidized to improve bonding properties.
• Sizing: Fibers are coated and wound onto bobbins,
which are loaded onto spinning machines that twist the
fibers into different size yarns. Rather than being
woven into fabrics, fibers can also be formed into
composite materials, using heat, pressure, or a vacuum
to bind fibers together with a plastic polymer.

16. PROPERTIES OF
CARBON FIBRES
• Brittle nature
• Good tensile strength
• Electrical and thermal conductivity
• Light weight
• Black in color
• Resistance to corrosion
• Chemically stable
• Fire resistant
• low Coefficient of thermal
expansion

17. APPLICATIONS OF CARBON FIBERS
• Aerospace and Aircraft industry
• Civil Engineering
• Sports Appliances
• Acoustics
• Portable power sources
• Textile industry
• Paper industry
• Automotive parts
• Energy production