Its name was given to the honeycomb sheet of carbon atoms. It is the basic and fundamental building block of other allotropes of carbon like graphite, charcoal and carbon nanotubes allotrope which contains a single layer of atoms embedded in two-dimensional hexagonal lattice commonly classified as 2D material. It is about one atom thick roughly 1/1000th of a paper. It has four outer electrons which are bonded to 3 other carbon atoms in 2 dimensions It has a tensile strength of 130GPa and possesses great plastic properties.
It possesses a strength that is 100 times more than the steel, has a lower density than aluminium and is also a good conductor of heat and electricity about 13 times when compared to copper and is nearly transparent. The thermal conductivity is much better when compared to diamond and graphite. It has a specific surface area of 2639 m2/g.
The stability of graphene is attributed to the tight bonds between the carbon atoms and the sp2 hybridization which are responsible for the intrinsic mechanical properties like strength, toughness. Defects within a sheet increase its chemical reactivity and it burns at a low temperature. At 350-degree centigrade graphene is a zero-gap semiconductor because of its ultra-lightweight. Its electron mobility is 100 times faster as compared to silicon conduction.
Graphene use in steel
Although stainless steel is more resistant to corrosion when compared to other metals but it can be susceptible to attack in acidic, aqueous environments which can result in cracking. The natural hydrophobic properties of graphene have the capacity to repel water from the surface of stainless steel fibers. In addition, graphene’s electrical properties reduce the likelihood of redox reactions occurring on the surface, preventing oxidation of the substrate metal.
Carbon Nanotubes and Carbon Nanofibers
Carbon nanotubes are simply layers of graphene which are wrapped into perfect cylinders. Carbon nanofibers are made from layers of graphene as well but arranged into the shapes of stacked cones, cups, or plates. These materials can be combined with bulk building materials to improve or add new properties to the bulk materials. Possible applications include replacing steel cables on suspension and cable-stayed bridges with much stronger carbon nanotubes. Carbon nanotubes can be embedded into concrete which can serve as supportive fibers and the resulting concrete has the capability to handle stress and compression which is far better when compared to the traditional concrete.
Tata Steel has launched graphene stirrups known as Tiscon Superlinks+ which has better corrosion resistance and enhanced bond strength.
Tata Steel and UK engineering and physical sciences research council have entered into a partnership to develop graphene-coated steel and had also signed a collaboration agreement with Talga to explore opportunities on graphene supply, processing, and application.
A graphene development cell has been set up by the company to identify its applications and establish new businesses for the company. Advanced material research centers have been set up at Chennai, in collaboration with the Indian Institute of Technology, Chennai and at Bengaluru with the Center for Nano and Soft Matter Sciences.
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