DR. RAVI PRAKASH
Composite = Something made up of distinct parts(or
A materials system composed of suitably arranged
mixture or combination of two or more micro- or
macro constituents with an interface separating
them that differ in form and chemical composition
and are essentially insoluble in each other.
What is Carbon Fiber ?
Composed of carbon atoms bonded together to
form a long chain.
A super strong material that's also extremely
Five times stronger than steel , Two times stiffer ,
and about Two-Third times less in weight.
Thin strands of carbon- even thinner than human
Strands can be twisted together, like yarn- can be
woven together, like cloth extremely lightweight.
How is Carbon Fiber Made?
Production from two sources -:
The raw material used to make carbon fiber is called the
In General Carbon fiber are produced in three
In the stabilization stage, the PAN fibers are first
stretched to align the febrile networks within each
fiber axis, and they are oxidized in air at about 200
to 220C while held in tension.
In carbonization the stabilized PAN-based fibers are
pyrolyzed (heated) until they become transformed
into carbon fibers by the elimination of O,H & N
from the precursor fiber.
The carbonization heat treatment is usually carried out in
inert atmosphere in the 1000 to 1500C range. During the
carbonization process, turbostratic graphite like fibrils or
ribbons are formed within each fiber that greatly increase
the tensile strength of the material.
In the third stage , or graphitization treatment is used if
an increase in the modulus of the elasticity is desired at
the expense of high tensile strength. During
Graphitization, which is carried out above about 1800C ,
the preferred orientation of the graphite like crystallites
within each fiber is increased.
Carbon fiber are produced from Pitch precursor as
Production of carbon fiber is initiate by process
known as polymerization , when pitch is heated at
300C, several carbon aromatic rings chain combines
with Each other & generate stable sheet type 2-D
structure which is known as misophase of pitch.
This mesophase of pitch is now wrapped around
spinner while passing through die the misophase will
aligned in the filament direction.
Filaments are cooled to freeze the molecular
orientation again to stabilize the chain of the
polymerized structure, it is heated in a range of
200C-400C. In an oxygen containing environment to
stabilize the structure as well as to make them
infeasible structure .
In the next step the filaments are carbonized at the
temp of 1000C in the presence of inert gas.
Carbonization remove all the O,H & N atoms from
the molecule of the pitch. Hence contained arranged
After carbonization if it is required to incraese
mechanical property of this carbon fiber it can be
again heat treated by process known as
In Graphatization , it is heating carbonized carbomn
fiber in the range of 200C or above in the vaccume.
After graphitizaion the mechanical strenth capability
is at maximum level which is a PAN carbon fiber can
Carbon fiber has very high tensile strength.
It has low thermal expansion.
It is a light weight material having low density.
It is a good conductor of electricity.
It can wear a high resistance.
It has long working life.
It’s density is less than density of steel.
It is insensitive to change in temperature.
It’s properties is much better than any of the other
It’s compressive strength is greater than all the
It is very costly.
It is little bit harmful for the human body as it cause
some form of cancer of the lungs.
It is mostly used in the aerospace and aircraft
It is used in making sports equipment such as light
weight badminton rackets, golf stick etc.
Automotive body is also made up of the carbon
India gets first carbon fiber plant
May 9th 2010, Former President Dr A P J Abdul
Kalam on Sunday inaugurated the country's first
carbon fibre manufacturing facility. The Rs 250crore set up will produce lightweight material for use
in defence, aerospace and infrastructure — under
technology transfer from the Council of Scientific
and Industrial Research's (CSIR) National Aerospace
Laboratory (NAL), which had developed the ultralight material for the Light Combat Aircraft.