« Workshop Nanocoatings », Liège, January 15, 2015
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« Workshop Nanocoatings », Liège, January 15, 2015
Introduction (1) – Interesting prospects • Use of nanoparticles in metal matrix composites
– For new functions e.g. self cleaning
– For enhanced properties e.g. better wear or corrosion resistance, electrical and thermophysical properties…
• New applications of metallic materials • … but there are some challenges…
– Development of innovative processing routes e.g. solid-state processes such as Friction Stir Processing
• … and phenomena that are specific to MMNCs
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Introduction (2) - Challenges
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Friction Stir Processing of Cu + nano-particles of Y2O3
• Nanoparticles have a strong tendency to agglomerate • Homogeneous distribution is of paramount importance!
[Avettand-Fenoël et al., 2014]
3 passes 9 passes
Dispersion is more homogeneous
Introduction (3)
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FSP of Mg + carbon nanotubes (CNTs)
• Nano-particles may also cause changes in the metallic matrix! E.g. by affecting nucleation of new grains during solidification/recrystallisation or by pinning the grain boundaries ⇒ Refinement of the microstructure
• Strong effect can be obtained for small amount of nanoparticles
[Mertens et al., ULg-UCL]
Base Material FSP (9 passes) Mg + nanotubes de C
Hardness (HV10) Grain size (µm)
FSP (9 passes) 58.9 ± 0.2 17.0 ± 4.8
Mg + CNTs composite 68.7 ± 0.5 3.8 ± 1.2
Outline
• Introduction – Metal Matrix Nano-Composites – Interesting prospects… – … and new challenges – Nano-particles may also cause changes in the metallic matrix!
• Enhanced properties for new applications – Corrosion resistance – Wear resistance – Physical and termophysical properties – Others
• Summary • Acknowledgements • References
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Improved corrosion resistance (1)
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Ni + SiC nano-particles coating produced by co-deposition • The nano-composite
coating exhibits better corrosion resistance in salt spray cabinet
• The nano-composite coating is more compact and provides a better surface coverage
[Lekka, 2005]
Ni Ni + SiC During co-deposition, surfactants must be used to favour a good dispersion of the nano-particles in the suspension
Improved corrosion resistance (2)
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NiCrMoNb alloy + nano Y2O3 deposited by laser cladding • A powder is projected onto a
substrate and melted in a laser beam ‒ Mixture of two different powders… ‒ … or a composite powder
• Functionally
graded coatings
Lower current density at high potential
[Pér
ez, 2
012]
[Gu,
201
4]
Outline
• Introduction – Metal Matrix Nano-Composites – Interesting prospects… – … and new challenges – Nano-particles may also cause changes in the metallic matrix!
• Enhanced properties for new applications – Corrosion resistance – Wear resistance – Physical and termophysical properties – Others
• Summary • Acknowledgements • References
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Improved wear resistance (1)
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Ni + SiC coating produced by co-deposition
• The nano-composite coating exhibits better wear resistance compared to pure Ni and also to the micro-composite coating
• This effect is even stronger at high temperature
• The amount of nano SiC in the coating is very low i.e. 0,18 wt%
• Grain refinement and loss of preferential crystallographic orientation in the Ni matrix of the nano-composite play an important role!
[Lekka, 2012]
Room Temperature
300°C
Improved wear resistance (2)
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Ni + SiC coating produced by co-deposition
• The nano-composite coating exhibits better wear and scratch resistance compared to the micro-composite coating
• The micro-composite coating exhibits a higher surface roughness than the nano-coating
• Micro-particles may be chipped away from the coating and then contribute to accelerate wear [Narasimman, 2012]
Nano SiC
Micro SiC
Improved wear resistance (3)
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Ni + nano ZrO2 coating deposited by plasma spraying
• A good dispersion of the nano-particles is essential to improve wear performances
• Nano-particles clusters tend to act similarly to micro-particles
[Fernandes, 2013]
Mixture of 2 powders
One composite powder
Outline
• Introduction – Metal Matrix Nano-Composites – Interesting prospects… – … and new challenges – Nano-particles may also cause changes in the metallic matrix!
• Enhanced properties for new applications – Corrosion resistance – Wear resistance – Physical and termophysical properties – Others
• Summary • Acknowledgements • References
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Physical properties (1) - Electrical resistivity
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Cu + CNTs coating produced by co-deposition
• Current trends for miniaturisation in electronic devices ⇒ Need for Cu-based composite coatings with enhanced electrical conductivity / minimised electrical resistivity
• Carbon nanotubes appear very promising due to their high axial conductivity
• Resistivity of pure Cu: 1,89 µΩcm [Manu, 2013]
Conditions Percentage of CNTs (mass%)
Electrical resistivity (µΩcm)
Quiescent 1,2 2,11
Agitated 1,8 1,91
Variations in the morphology and porosity of the coatings
Physical properties (2) - Electrical conductivity
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Cu or Bronze + CNTs composites • Cu or bronze + CNTs
composites are produced by mechanical alloying + sintering
• Electrical conductivity of pure Cu is decreased by the addition of CNTs...
• ... but the electrical conductivity of bronze is increased
• Possibility to reach a good compromise between electrical and mechanical properties
[Uddin, 2010]
Physical properties (3) - Thermal expansion
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Cu + Al2O3 nanoparticles (in-situ synthesis) • Materials for heat sink
applications require the combination of a low CTE and of a high thermal conductivity
• Addition of Al2O3 nanoparticles allows decreasing the CTE
• But this comes at the expense of the thermal conductivity!
[Fathy, 2013]
At Room Temperature
Physical properties (4) - Thermal conductivity
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Cu + Y2O3 nanoparticles (FSP)
• A better compromise between a low CTE and a high thermal conductivity could be obtained by decreasing the volume fraction of nanoparticles (~0,7 vol.%)
[Shabadi, 2015]
Outline
• Introduction – Metal Matrix Nano-Composites – Interesting prospects… – … and new challenges – Nano-particles may also cause changes in the metallic matrix!
• Enhanced properties for new applications – Corrosion resistance – Wear resistance – Physical and termophysical properties – Others
• Summary • Acknowledgements • References
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"Self cleaning"
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Ni + TiO2 nanoparticles (codeposition) • Under UV irradiation,
TiO2 may give rise to the photocatalytic degradation of adsorbed pollutants
• Efficiency of this "self cleaning" effect depends − on the volume
fraction of TiO2 − on the texture in the
Ni matrix of the composite coating
[Spanou, 2013]
Degradation of Methyl Orange
Outline
• Introduction – Metal Matrix Nano-Composites – Interesting prospects… – … and new challenges – Nano-particles may also cause changes in the metallic matrix!
• Enhanced properties for new applications – Corrosion resistance – Wear resistance – Physical and termophysical properties – Others
• Summary • Acknowledgements • References
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Summary Metal Matrix Nanocomposite Coatings open very interesting prospects due to enhanced properties • Improved corrosion resistance in aggressive environments for
applications in chemistry, energy... • Enhanced wear behaviour for use in a wide range of
engineering components submitted to severe tribological conditions
• Better physical and thermophysical properties for applications e.g. in electronics
• New functionalities e.g. "self cleaning" for use in building, automotive industry...
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Acknowledgements • The MMS unit (ULg) and particularly H.M. Montrieux et S. Salieri • Sirris: J. Halleux et D. Garray • UCL: A. Simar and F. Delannay, along with the LAFAB team • For their financial support
– The Walloon Region (Winnomat Program) – The Interuniversity Attraction Pole Program, belgian office for scientific
policy, contract IAP7/21 “INTEMATE” – The European Development Funds and the Walloon Region (Belgium),
Project FEDER TipTopLam
• Thank you for your attention!
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References • M.-N.Avettand-Fenoël et al., Mater. Des., 60 (2014), 343 • A.Fathy and O.El-Kady, Mater. Des., 46 (2013), 355 • F.Fernandes et al., Wear, 303 (2013), 591 • D.Gu et al., Metall. Mater. Trans. A, 46 (2014), 464 • M.Lekka et al., Electrochim. Acta, 50 (2005), 4551 • M.Lekka et al., Surf. Coat. Technol., 206 (2012), 3658 • R.Manu and S.Priya, Appl. Surf. Sci., 284 (2013), 270 • P.Narasimman et al., Wear, 292-293 (2012), 197 • A.T.Pérez et al., Mater. Sci. Forum, 706-709 (2012), 2552 • R.Shabadi et al., Mater. Des., 65 (2015), 869 • S.Spanou et al., Electrochim. Acta, 105 (2013), 324 • S.M.Uddin et al., Comp. Sci. Technol., 70 (2010), 2253
Publications by ULg-MMS are available on http://orbi.ulg.ac.be/ Website ULg-MMS: http://www.metaux.ulg.ac.be/
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