Graphite has a wide variety of almost contradictory uses. An allotrope of carbon and one of the world’s softest minerals, its uses range from writing implements to lubricants.
It can be made into a one-atom-thick cylinder of graphene that is a super-strength material used in sports equipment. Graphite can behave like metal and conduct electricity but also as a nonmetal that resists high temperatures.
Graphite occurs naturally as flakes and veins within rock fractures or as amorphous lumps. The basic crystalline structure of graphite is a flat sheet of strongly bonded carbon atoms in hexagonal cells.
Called graphenes, these sheets stack above each other to create volume, but the vertical bonds between the sheets are very weak. The weakness of these vertical bonds enables the sheets to cleave and slide over one another.
However, if a graphene sheet is aligned and rolled horizontally, the resultant material is 100 times stronger than steel.
Uses of Graphite
Graphite is also used in pencils, steel manufacturing, and electronics such as smartphones. Perhaps its most important application is the lithium-ion battery, where graphite ranks above even lithium as the key ingredient. There is actually 10 to 30 times more graphite than lithium in a lithium-ion battery.
These are some uses of graphite:
- Writing Materials
- Nuclear Reactors
- Graphene Sheets
MORE: What is Graphite?
1. Writing and Artists Materials
The word graphite is from the Greek language which translates as ‘to write’. So the most common use of graphite is in making the lead in pencils.
“Lead” pencil cores are made of a mixture of clay and graphite, which is in an amorphous form. Loosely cleaved graphite flakes mark the paper, and the clay acts as a binding material. The higher the graphite content of the core, the softer the pencil and the darker its trace.
There is no lead in what is known as lead pencils. The name originated in Europe when graphite was called “plumbago” or “black lead” because of its metallic appearance.
Graphite’s use as a marker dates from the 16th century in northern England, where local legend states that shepherds used a newly discovered graphite deposit to mark sheep.
Graphite is one of the main ingredients in lubricants like grease, etc. Graphite reacts with atmospheric water vapor to deposit a thin film over any adjacent surfaces and reduces the friction between them. It forms a suspension in oil and lowers friction between two moving parts like car brakes and clutches.
Graphite works in this way as a lubricant up to a temperature of 787 degrees Celsius (1,450 degrees Fahrenheit) and as an anti-seize material at up to 1,315 degrees Celsius (2,399 degrees Fahrenheit).
This powerful mineral acts as a good repellant; hence a plethora of manufacturing companies use graphite as an ingredient in repellent solutions. One of the most common repellants that use graphite includes metal protectors.
If you have ever come across paints that guarantee the protection of walls, then you would be able to find graphite in them. In this case, the powder form of graphite comes into use. Factories mix the powdered graphite in paints to create authentic protection for the walls.
Graphite is a common refractory material because it withstands high temperatures and tolerance without changing chemically. It is used in manufacturing processes ranging from steel and glass making to iron processing. It is also an asbestos substitute in automobile brake linings.
5. Nuclear Reactors
The capacity of graphite to absorb fast-moving neutrons is very high, so most of the time, this mineral is very much in use to stabilize or neutralize the reactions of neutrons.
6. Electrical Industry
Crystalline flake graphite is used in the manufacturing of carbon electrodes, brushes, and plates needed in dry cell batteries and the electrical industry. Interestingly, natural graphite is also processed into synthetic graphite. This type of graphite is useful in lithium-ion batteries.
Lithium-ion batteries have a lithium cathode and a graphite anode. As the battery charges, positively charged lithium ions in the electrolyte a lithium salt solution accumulate around the graphite anode.
A lithium anode would make a more powerful battery, but lithium expands considerably when charged. Over time, the lithium cathode’s surface becomes cracked, causing lithium ions to escape. These in turn form growths called dendrites in a process that can short-circuit the battery.
7. Graphene Sheets
Rolled single graphene sheets are 10 times lighter, as well as 100 times stronger than steel. Such a rolled sheet is also referred to as graphene, and this derivative of graphite is the world’s strongest identified material and has been used to make super-strength, lightweight sports equipment.
Its high electrical conductivity, low light absorbance, and chemical resistance make it an ideal material for future applications, including in medical implants such as artificial hearts, flexible electronic devices, and aircraft parts.
Application of Graphite
Graphite is used in pencils and lubricants. It is a good conductor of heat and electricity. Its high conductivity makes it useful in electronic products such as electrodes, batteries, and solar panels. But also it has an industrial application of graphite as per below:
1. in the Chemical industry
In the chemical sector, graphite is employed in many high-temperature applications, like in the production of phosphorus and calcium carbide in arc furnaces. Graphite is used as an anode in specific aqueous electrolytic processes such as the production of halogens (chlorine and fluorine).
2. in the Nuclear industry
Large amounts of high-purity electrographite are used for producing moderator rods and reflector components in nuclear reactors. The suitability of electrograms comes from the low absorption of neutrons, high thermal conductivity, and high power at high temperatures.
3. Electrical applications
Graphite is mainly used as an electric material in the manufacture of carbon brushes in electric motors. Here, the component’s service life and performance largely depend on grade and structure.
4. Mechanical applications
Graphite is widely used as an engineering material across a variety of applications such as piston rings, thrust bearings, journal bearings, and vanes. Carbon-based seals are used in the fuel pumps and shafts of several aircraft jet engines.
4.1. Seal rings & Turbine rings:
Used alongside graphite guide rings to seal high-pressure, oil-free gases. Because of Self-lubricating, chemically inert, high strength-to-weight ratio, thermal stability
4.2. Slip rings & Sliding rings
Electromechanical devices are designed to transmit electrical current from a stationary device to a rotating one. They improve mechanical performance and remove the need to have wires dangling from movable joints. Graphite use Because of its Conductivity, self-lubricating properties that mean it can resist wear over time.
4.3. Bearings & Bushings
Bearings are components that support a load while in contact with and moving relative to another part. A type of bearing, bushings are thin tubes designed to reduce friction between two surfaces sliding against each other. Graphite use Because of its Self-lubricating, long service life, thrives in harsh environments.
Blades are attached to a rotating wheel that pushes or is pushed by wind or water. Graphite use Because of its Self-lubricating, resistant to high temperatures, chemically inert.
4.5. Lubrication blocks
Designed to lubricate rotary equipment such as trunnion rolls, riding rings, tires, and insert seals where wet lubricants can’t be used. The weight of the block keeps it in constant contact with the rolling surface, depositing a thin film of graphite. Graphite use Because of its Self-lubricating, resistance to wear over time