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GRAPHENE COATING : AN EFFICIENT PROTECTION FROM OXIDATION FOR METALS GUIDED BY, Mr. Babu Sanker S. Asst.Prof in Mech. Engg PRESENTED BY, Nithin Babu S 7 ME B 19 1

Graphene coating

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Page 1: Graphene coating

GRAPHENE COATING : AN EFFICIENT PROTECTION FROM OXIDATION

FOR METALS

GUIDED BY,

Mr. Babu Sanker S.

Asst.Prof in Mech. Engg

PRESENTED BY,

Nithin BabuS 7 ME B

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OVERVIEW

Graphene

Properties of graphene

Graphene sythesis

Coating method

Experiment setup

Characterization

Results

Conclusion

Reference

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WHAT IS GRAPHENE????

• 2-dimensional, crystalline allotrope of carbon

• Single planar sheet of sp2 bonded C atom

• Basic structural element of other allotropes,

including graphite, carbon nanotubes and

fullerenes

• C –C bond lengh in graphene is .142 nm

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PROPERTIES OF GRAPHENE….

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CHEMICAL PROPERTIES

• Graphene is chemically the most reactive

form of carbon.

• Only form of carbon in which each single

atom is in exposure for chemical reaction

from two sides (due to the 2D structure).

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ELECTRONIC PROPERTIES

• It is a zero-overlap semimetal with very

high electrical conductivity

• Electrons are able to flow through

graphene more easily than through even

copper.

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Optical Properties

• Graphene, despite it is only 1 atom thick,

is still visible to the naked eye.

• Due to its unique electronic properties, it

absorbs a high 2.3% of light that passes

through

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MECHANICAL PROPERTIES

• Graphene is harder and stiffer than

diamond and about 300 times harder than

steel.

• It is flexible & strechable. It is strechable

up to 20% of its intial length

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GRAPHENE SYTHESIS

Chemical Vapour Deposition (CVD)

Mechanical Exfoliation

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(d) desorption of adsorbed species

(a) diffusion of reactants through boundary layer,

(b) adsorption of reactants on substrate,

(e) diffusion out of by-products through

boundary layer

(c) chemical reaction takes place,

Figure 1 : CVD process

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Figure 2: Mechanical exfoliation of graphene

(a) Adhesive tape is pressed onto the HOPG.(b) The tape is peeled off when some layers stick

to the surface.(c) The tape is pressed onto the surface of target

substrate.(d) The tape is peeled off when the layers stick to

target surface. 11

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COATING METHOD

CONVENTIONAL COATINGS

• coating with organic layers, paints or

varnishes, polymers, formation of oxide

layers, chemical modification, and coating

with other metals or alloys.

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CHALLENGE

• modify the physical properties of metals

• Increase thickness of the coating

• changes the appearance and the optical properties of the metal surface

• decreases the electrical and thermal conductivity.

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GRAPHENE COATING

• Graphene has exceptional thermal and

chemical stability

• It is optically transparent (approximately

2.3% absorption per layer) in visible

wavelengths

• Electrically and thermally conductive.

• It adds only about 0.34 nm per layer to the total dimension of the coated metal.

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EXPERIMENT SETUP

PREPARATION

• Large-area graphene samples were grown on metal substrates using CVD techniques.

• Growth of graphene on Cu foil was performed in a hot wall tube furnace at a temperature of 1040 OC with 5% H2 in CH4 at a pressure of 500 mTorr.

• Growth of graphene on Cu/Ni (31% Ni, 67.8% Cu, 0.45% Mn,0.60% Fe) was performed in the cold-wall CVD system at a growth temperature of 1000 OC with pure CH4 at a pressure of 8 Torr.

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CHARACTERIZATION

SCANNING ELECTRON MICROSCOPY

X-RAY PHOTOELECTRON SPECTROSCOPY

(XPS)

RAMAN SPECTROSCOPY

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RESULTS

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CONCLUSION

• This seminar demonstrate the excellent performance of graphene as a protectivelayer. Its chemical inertness to oxidizing gasallows for its use in a wide variety of environments.

• The main limitation of this protection technique is its deactivation after mechanical damages.

• Graphene coating disappears when subjected to air annealing at 600 °C.

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• So, graphene as oxidation resistance is only effective up to post annealing of 500 °C.

• With further advances in graphene growth and careful control of the metal catalyst, it may anticipate a significant improvement in the level of protection of these films.

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REFERENCES

1. Shanshan Chen ; Lola Brown; and Mark Levendorf , Oxidation Resistance of Graphene Coated Cu and Cu/Ni Alloy VOL. 5,NO. 2, 2011 ,PP1321–1327

2. Pramoda K. Nayak ;and Chan-Jung Hsu, Graphene coated Ni films: A protective coating, Thin Solid Films,2012

3. M. Topsakal ; H. Sahin ; and S. Ciraci, Graphene coatings: An efficient protection from oxidation,2012

4. Segarra, M.; Miralles, L.; Diaz, J.; Xuriguera, H.; Chimenos,

J. M.; Espiell, F.; Pinol, S. Copper and CuNi Alloys Substrates

for HTS Coated Conductor Applications Protected from

Oxidation. Mater. Sci. Forum ,2003,PP 3511–3516.

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THANK YOU

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