Flexible Graphite
Introduction
Graphite Tapes and sheets are binderless products obtained by the compression of exfoliated graphite particles. It has large potential for use in areas where asbestos has been used conventionally - primarily as sealing material for gaskets and packings.
The specific nature and inherent characteristics of compressed exfoliated graphite give rise to the following features.
- This material is impermeable to gases and liquids and can act as a good sealant.
- It is temperature resistant and can be used from 2000 C to 5000 C in oxidising atmosphere and upto 3000 0 C in an inert or reducing atmosphere.
- It does not age or creep.
- It is not wetted with molten glass, metals etc.
- It is self-lubricating and can be easily cut and punched.
- It is resistant to radiation doses of any magnitude occurring in nuclear power stations.
- It is flexible and exhibits high corrosion resistance.
- This material can be used under high temperature and corrosive environments as sealing material, packings and linings. The major applications of flexible graphite are as :
- Gaskets and linings in the automotive sector.
- Protective material in tubes and containers against corrosive and hot gases.
- Lining for crucibles and casting moulds.
- As sealant and packing in the chemical and petrochemical industry.
- As lining and sealant in the nuclear power industry.
- As an electrode for high energy density battery.
Flexible graphite with its superior properties, is eco-friendly and can replace conventionally used asbestos which is a hazardous material and banned throughout the world, and therefore, possesses very high potential for use in automobile and engineering industry throughout the world.
Process
The natural graphite flakes is treated with acids and chemicals, washed and dried, and then exfoliated in a specially design furnace wherein it expands in o-direction upto 300 times. The exfoliated fluffy material is put into mould and pressed into sheet under hydraulic press. The sheets are then cut and punched in suitable gaskets or cut in the form of strips and rolled and repressed into seals of desired shape and size.
Characteristics |
Value |
| Tensile strength | 65 Kg/cm2 |
| Strain to failure | 1.2 - 1.3% |
| Compressibility | 14 % at 70 Kg/cm2 30 % at 350 Kg/cm2 |
| Coeff. of thermal expansion | 30 x 10-6 c-1 ( in o - direction 300 - 8000 C) |
Plant Parameters
| Capacity, TPA | 3000 |
| Number of shifts | 1 |
| Working days / Yr. | 300 |
| Land Area., m2 | 500 |
| Covered Area, m2 | 300 |
Manpower
| Managerial | 2 |
| Skilled worker | 6 |
| Unskilled worker | 15 |
Raw Material (Tonnes per tonne of product)
| Graphite flakes | 1.2 |
| Chemicals | - |
Utilities ( per day)
| Power, KwH | 50 |
| Water, KL | 1 |
Plant & Machinery
| Oven | Hydra. Press |
| Exfoliation Furnace | Die |
| Balance | Hand Cutter |
| Hand Cutter | Glass ware |
Advantages of Indian technologies
- Low capital investment
- High employment potential
- Maximum use of local raw materials and manpower resources
- Adaptable levels of sophistication
For further information please contact
National Research Development Corporation
( A Government of India Enterprise )
20-22, Zamroodhpur Community Center
Kailash Colony Extension
New Delhi 110 048. India
Tel: 91-11-26419904, 26417821, 26480767, 26432627
Fax: 011-26231877, 26460506, 26478010
Website: www.nrdcindia.com
