-
VIZ GRAF, Busteni, October 2006 1
RESULTS AND TRENDS RESULTS AND TRENDS IN THE DEVELOPMENT OF IN
THE DEVELOPMENT OF
NANOCOMPOSITE NANOCOMPOSITE MATERIALSMATERIALS
Radu L. OrbanRadu L. Orban
Technical University of ClujTechnical University of
Cluj--NapocaNapocaROMANIAROMANIA
-
VIZ GRAF, Busteni, October 2006 2
Nanocomposite materials Nanocomposite materials iinspired from
the naturenspired from the nature
BBiological materials join together:iological materials join
together:-- sensingsensing-- actuation actuation --
healinghealing-- other propertiesother properties
built into the primary built into the primary
structurestructureof an organismof an organism
Extension to materials design :Extension to materials design :--
mechanicalmechanical-- electricalelectrical--
electronicelectronic-- magneticmagnetic-- optical, etc. optical,
etc.
integrated functionsintegrated functions
-
VIZ GRAF, Busteni, October 2006 3
How to get these integrated functions ?How to get these
integrated functions ?combining combining metallic, ceramic,
polymericmetallic, ceramic, polymeric materials to a :materials to
a :
-- nanometricnanometric-- molecularmolecular-- atomicatomic
| scalescale to work in synergyto work in synergyExpected
properties :Expected properties :
beyond those of the sum of individual capabilitiesbeyond those
of the sum of individual capabilities
incorporated intelligenceincorporated intelligence high added
valuehigh added value
The new, as obtained, The new, as obtained, nanocomposite
materialsnanocomposite materials | IntermaterialsIntermaterials
-
VIZ GRAF, Busteni, October 2006 4
PossibilitiesPossibilitiesto obtain nanocomposite structures to
obtain nanocomposite structures Intra-type
High strength and reliability, Excellent HT High strength and
reliability, Excellent HT mechanical properties, High
toughnessmechanical properties, High toughness
Super tough and strong(at room and high temperatures)
Micro/Nano Hybrid - type Mutual Nano - type
Micro - sized particles,whisker or fibers
Phase A Phase B(A/B + B/A)
New functions:New functions:MachinabilityMachinability
SuperplasticitySuperplasticity
Inter-type Intra/Inter-type Nano/Nano-type
Nano dispersion
Intra-type
K. Niihara, 4th International PM Conference of Turkey, Sakarya
2005
-
VIZ GRAF, Busteni, October 2006 5
Common Bulk Nanocomposites
Strongly improved mechanical properties
Metal/Ceramic/PolymerMetal/Ceramic/Polymer--Ceramic/Metal
Ceramic/Metal
SystemsSystems
Structural MaterialsStructural Materials
Nanoparticles
Micro Matrix
Ceramic-Pores Nanocomposites
Permeability, High Fracture Toughness, Strength
CeramicCeramic--Nanopores SystemsNanopores Systems
Metal/Ceramic-Carbon Nanocomposites
Metal/CeramicMetal/Ceramic––Carbon SystemsCarbon Systems
Hard/Soft Nanocomposites
Mechanical Properties, Machinability
CeramicCeramic--Metal, CeramicMetal,
Ceramic--CeramicCeramicSystemsSystems
Micro/Nano Composites
Nano Sized2nd Phase
Matrix
High Fracture Toughness, Strength
MetalMetal--Ceramic, CeramicCeramic, Ceramic--Metal, Metal,
CeramicCeramic--Ceramic SystemsCeramic Systems
In-grain toughening
Micro Sized2nd Phase
Carbon Nanotubes/Fullerenes
Matrix
Soft 2nd Phase
Hard Matrix
Novel Nano Processing
Nanopores
Matrix
Grain BoundaryControl Concept
Polymer Based Polymer Based NanocompositesNanocomposites
Metal Based Metal Based NanocompositesNanocomposites
Ceramic based Ceramic based NanocompositesNanocomposites
High Strength, Fracture Toughness
micro/nano
Bulk Nanocomposite MaterialsBulk Nanocomposite Materials
-
VIZ GRAF, Busteni, October 2006 6
Recent achievements Recent achievements in nanocomposites
developmentsin nanocomposites developments
⎪⎪
Common Metal Matrix Nanocomposites (MMNCs)*
Modern method of MMNCs production:
InIn--situ reactive synthesis situ reactive synthesis of
reinforcing phases in the metalof reinforcing phases in the
metalmatrix melt / powder compactsmatrix melt / powder compacts
-- Reinforcing particles:Reinforcing particles:-- nanometric
size nanometric size -- thermodynamically stable, thermodynamically
stable, -- uniformly distributeduniformly distributed
-- Cleaner interfacesCleaner interfaces-- Energy savingsEnergy
savings
Matrix materials : Matrix materials : Al, Ti, Ni, Cu, Fe,
various alloysAl, Ti, Ni, Cu, Fe, various alloys
Reinforcing phases : Reinforcing phases : oxides, carbides,
borides, nitridesoxides, carbides, borides, nitrides
-
VIZ GRAF, Busteni, October 2006 7
Possible reactions ofPossible reactions ofMMNCs Reactive
Processing* MMNCs Reactive Processing*
Synthesis reactionsSynthesis reactionskM + mR + nC kM + RmC n
(1)(m+p)R +nC pR + RmCn (1’)
Displacement reactionsDisplacement reactions
MMkkTT nn + mR + mR kM + RkM + RmmTTnn (2)(2)
kM + MkM + MppTTnn+mR +mR (k+p)M +R(k+p)M +RmmTTnn (2(2’’))
kM + mR + XkM + mR + XttTTn+qn+q kM + RkM + RmmTTnn + X+ XttTTq
q (3)(3)
Thermodynamic condition:Thermodynamic condition: ΔΔGG00f/rf/r
< 0< 0* R.L. Orban, Proceedings RoPM 2000, Cluj-Napoca
-
VIZ GRAF, Busteni, October 2006 8
Thermodynamic possibilities Thermodynamic possibilities of
reactive processing of MMNCs*of reactive processing of MMNCs*
Oxide RCs inOxide RCs in--situ synthesissitu synthesis
Carbides/Borides RCsCarbides/Borides RCsinin--situ synthesissitu
synthesis
-1500
-1000
-500
0
500
1000
0 500 1000 1500 2000 2500 3000
Temperature, T [K]
Stan
dard
Gib
bs F
ree
Ener
gy o
f For
mat
ion,
ΔG
0f [k
J/m
ol]
Al + 2/3Al2O3 + Zr = 7/3Al + ZrO2Ti + 2Al + 1.5TiO2 = 2.5Ti +
Al2O3Ti + Zr + TiO2 = 2Ti + ZrO2Ti + 3Al = TiAl3Ni + 2Al + 3NiO =
4Ni + Al2O3Ni + Zr + 2NiO = 3Ni + ZrO22Ni + 3Al = Ni2Al3Cu + 2Al +
3CuO = 4Cu + Al2O3Cu + Zr + 2CuO = 3Cu + ZrO2Fe + 2Al + Fe2O3 = 3Fe
+ Al2O3Fe + Zr +2/3 Fe2O3 = 7/3Fe + ZrO2
-350
-300
-250
-200
-150
-100
-50
0
50
100
0 500 1000 1500 2000 2500 3000 3500
Temperature, T [K]
Stan
dard
Gib
bs F
ree
Ener
gy o
f For
mat
ion,
ΔG
0 r [k
J/m
ol]
Ti + C = TiC2Ta + C = Ta2CNb + C = NbCV + C = VC4B + C = B4C4Al
+ 3C = Al4C33Fe + C = Fe3C3Ni + C = Ni3C3Al + Ti = Al3Ti3Ni + Ti =
Ni3TiTi + 2B = TiB2Zr + 2B = ZrB2Al + 12B = AlB12Fe + B = FeB4Ni +
3B = Ni4B3
-
VIZ GRAF, Busteni, October 2006 9
Bulk metalsBulk
metalsmultifunctionalisationmultifunctionalisationCu/Ni (~500Cu/Ni
(~500 nm) + nm) + (3.3(3.3÷÷5.6) wt.% Al5.6) wt.% Al22OO33 (20
nm)(20 nm)
-- Higher mechanical strength than Cu/Ni (~1.5 x)Higher
mechanical strength than Cu/Ni (~1.5 x)
-- Higher hardness / wear resistance, Higher hardness / wear
resistance, endurance limit (4endurance limit (4÷÷6 x)6 x)
-- The same electrical conductivity/ The same electrical
conductivity/ magnetic properties / corrosion magnetic properties /
corrosion resistance as resistance as Cu / Ni pure metalsCu / Ni
pure metals
Applications : Applications : -- heavy duty electrical contacts
heavy duty electrical contacts -- magnetic cores for hostile
environments etc.magnetic cores for hostile environments etc.
-
VIZ GRAF, Busteni, October 2006 10
WW--Cu nanocompositesCu nanocomposites- higher strength than
similar
crystalline materials fabricated by liquid phase sintering /
infiltration
- lower thermal expansion coefficient
Applications :- heavy duty heavy duty electrical
contactselectrical contacts-- electrodes for electroelectrodes for
electro--dischargedischarge
machining, shape charge linersmachining, shape charge
linersNanocrystalline Cemented Nanocrystalline Cemented
carbidescarbides very thin tools, e.g. drilling tools very thin
tools, e.g. drilling tools
ØØ < 0.5 mm< 0.5 mm
3
4
5
6
7
8
9
0,05 0,1 0,15 0,2 0,25 0,3
Cu content, [wt. fraction]
CTE
, [pp
m /
K]
NanocompositeComposite by infiltration 1Composite by
sinteringComposite by infiltration 2
-
VIZ GRAF, Busteni, October 2006 11
Nanocomposites Nanocomposites
(Intra&Intergranular)(Intra&Intergranular)
Notable enhancement of:Notable enhancement of:-- Mechanical
Mechanical and thermal propertiesand thermal properties
-- Homogeneity atHomogeneity atthe nanoscalethe nanoscale
-- Physical andPhysical andchemical propertieschemical
properties
Addition of new functionsAddition of new functionsGradual
components Gradual components dispersion dispersion FGMFGM
Monolithic and/or Monolithic and/or
MicroMicro--compositescomposites
- Mechanical properties are notenough high e.g. toughness
- Inhomogeneity ofmicrostructure, mechanical,physical
properties
Bulk nanocrystalline ceramicsBulk nanocrystalline
ceramicsNecessity of further Necessity of further improvements /
improvements /
multifunctionalisationmultifunctionalisationStructure control at
nanoStructure control at nano--scalescale
G.B. modification (Intergranular N.Cs.)
VVery small additions ery small additions of secondary
phase(s)of secondary phase(s)
Homogeneity in nano and/or molecular-scalePhysical properties
enhancementAddition of new functions: electric, optical,
etc.Reliability enhancement
K. Niihara, Key Engineering Materials, Vols. 161-163 (1999), pp.
527-534.
-
VIZ GRAF, Busteni, October 2006 12
CeramicCeramic--metal nanocompositesmetal nanocompositesAl2O3 -
(W, Mo, Ti, Ni, Co, Fe, FeNi)ZrO2 - (Mo, Ni. Co)MgO - (Fe,
Ni)Mullite - (Ni, Co, FeCo)SiC – (Al, AlSi, AlZn, AlMg)
CeramicCeramic--ceramic ceramic
SHSSpark PlasmaSintering
Two-stepsinteringElectrophoresisInfiltration
Al2O3 - (SiC, ZrO2 , TiC, TiN, TiB2, BN) MgO - SiC Si3N4 - (SiC,
TiN, BN, ZrO2 ) B4C - SiC, B4C – SiC+ TiB2
IntermetallicIntermetallic--ceramic ceramic NiAl NiAl ––
AlAl22OO33 –– TiBTiB2 2 * * SHS under pressure SHS under
pressure
* R.L. Orban, M. Lucaci,, 16th International Plansee Seminar,
Reutte, Austria 2005 High Performance PM Metals, vol. 1, p. 1170-
1180
-
VIZ GRAF, Busteni, October 2006 13
AlAl22OO3 3 -- SiC nanocompositeSiC nanocompositeAl2O3
monolith
Al2O3/5vol%-SiC Nanocomposite
Typical SEM Microstructure Intragranular SiC dispersion
K. Niihara, 4th International PM Conference of Turkey, Sakarya
2005
-
VIZ GRAF, Busteni, October 2006 14
SiSi33NN44 (SiC, Al(SiC, Al22OO33, ZrO, ZrO22) ) ––
SiNSiNnanocompositenanocompositeTo improve machinability, To
improve machinability,
toughnesstoughnessSi3N4/SiC/ZrO2/Al2O3 (powder)
+H3BO3
+CO(NH2)2 (urea)
Ball Milling
H2Reduction
Si3N4 nanopowder + BN precursor coating
(t-BN)
HPSintering
Si3N4//SiC/ZrO2/Al2O3 -hBN
NanocompositeK. Niihara, 4th International PM Conference of
Turkey, Sakarya 2005
-
VIZ GRAF, Busteni, October 2006 15
4mm4mm4mm
SiSi33NN44 (SiC, Al(SiC, Al22OO33, ZrO, ZrO22) ) –– SiN SiN
nanocompositenanocompositeMultifunctinality realised :
-- High strength at room and elevated temperaturesHigh strength
at room and elevated temperatures
-- Higher toughnessHigher toughness-- Lower hardness and Young's
ModulusLower hardness and Young's Modulus
-- QuasiQuasi--plasticityplasticity- Good machinability
(>15vol%hGood machinability (>15vol%h--BNBN))-- Excellent
thermal shock resistanceExcellent thermal shock resistance- Good
corrosion resistance to molten metals
SiSi33NN44 –– SiC nanocompositeSiC
nanocompositesuperplasticitysuperplasticity
Properties : - mutual C-CNCsStrength: 1.2 GPa (RT); 1.0 GPa
(1000 oC)KIC : 8 MPam 1/2
-
VIZ GRAF, Busteni, October 2006 16
Bulk polymer nanocompositesBulk polymer nanocomposites
Polymer – metal nanocompositesPolymers Polymers –– metallic
nanopowders (Ag, Cu, Ni, Fe, magneticmetallic nanopowders (Ag, Cu,
Ni, Fe, magneticalloys) alloys) mechanical / electrical / magnetic
/ decorativemechanical / electrical / magnetic /
decorativemultifunctionalisationmultifunctionalisation
Polymers (Polymers (thermoplastics) / Elastomers thermoplastics)
/ Elastomers ––metallic/ceramic nanopowders /
nanotubesmetallic/ceramic nanopowders / nanotubes--
nanopowders/nanotubes nanopowders/nanotubes high specific surface
area high specific surface area
difficulties in incorporation into polymer matrix difficulties
in incorporation into polymer matrix surfactantssurfactants
Polymer – ceramic nanocompositesPolymers Polymers –– ceramic
nanopowders (SiOceramic nanopowders (SiO22, Al, Al22OO33, clay
etc.) , clay etc.) mechanical / electrical /electronic /
opticalmechanical / electrical /electronic / optical
multifunctionalisationmultifunctionalisation
-
VIZ GRAF, Busteni, October 2006 17
Polymer (pPolymer (polypropylene, nylon etc.olypropylene, nylon
etc.) ) ––clay nanocompositesclay nanocomposites
Clay (Clay (montmorillonite)montmorillonite)a multilayer
aluminoa multilayer alumino--silicatesilicate
-- interinter--layer layer spacing in the nanometric range
spacing in the nanometric range organophobicorganophobic vs. vs.
organic compounds organic compounds surfactants surfactants
organoclay organoclay delaminated delaminated layers layers ~ 1
nm thickness / high aspect ratios (10 ~ 1 nm thickness / high
aspect ratios (10 ÷÷100)100)
Two types of composites Two types of composites
delaminated (exfoliated) delaminated (exfoliated)
montmorillonite montmorillonite layered crystal structurelayered
crystal structure
intercalatedintercalated
Properties (Nylon+5wt.% Clay)
- 68 % higher E; 126 % higher G- 60 % higher σfl; tdistorsion:
65 152 0C
-
VIZ GRAF, Busteni, October 2006 18
Mechanical multifunctionalisation Mechanical
multifunctionalisation through Carbon nanotubesthrough Carbon
nanotubes
a) Single wall SWCNT
b) Multi-wallMWCNT
7.89.00.8207Steel
2.716.00.569Aluminium
4.515.00.9103Titanium
1.61.22.1152Graphite fibre
1.81.52.71260MWCNT
1.44.065.01210SWCNT
Density(g/cm3)
Fracture Strain(%)
Yield Strength(GPa)
Elastic Modulus(GPa)Material
Mechanical properties of CNTs/common engineering
materialsMechanical properties of CNTs/common engineering
materials
ØØ = 2 = 2 ÷÷ 20 nm20 nmℓℓ < ~ 10 < ~ 10 μμmm
-
VIZ GRAF, Busteni, October 2006 19
Metal Metal –– Nanotubes nanocompositesNanotubes
nanocomposites
Ceramic Ceramic –– Nanotubes NCsNanotubes NCs
Polymer Polymer –– NanotubesNanotubes NCsNCs
Nanotubes fabricationNanotubes fabrication (Ni, Fe, Co etc.
catalysts) (Ni, Fe, Co) oxides + CNTs (MO-CNTs) nanocomposite
powders
Ni/Fe/Co + (MO-CNTs NP) (Me + MeO + CNTs) NCs- Properties:
Properties: UTS UTS 34 34 ÷÷ 37 % higher 37 % higher GearsGears
SiOSiO22 (quartz) + MWCNTs (quartz) + MWCNTs CMNCsCMNCs ((133
133 ÷÷ 146 %146 %higher toughness, preserving clarity, corrosion
resistance etc.)
CNTs CNTs high flexibility high flexibility bend during bend
during processing processing CNTsCNTs network interpenetrating
network interpenetrating the polymer matrix the polymer matrix High
mechanical resistanceHigh mechanical resistance
-
VIZ GRAF, Busteni, October 2006 20
Mechanical multifunctionalisationMechanical
multifunctionalisationthrough through nanocomposite
coatingsnanocomposite coatingsNanostructuredNanostructured coating
layerscoating layers (NSCLs)(NSCLs)
Nanosized hard compounds (SiC,TiC,TiN)+Me (Al, Ni) NSCLs low
friction coefficient, very high wear resistance
Nanostructured Diamond/DLC/TiN filmsNanostructured
Diamond/DLC/TiN films
CrystallineCrystalline NanocrystallineNanocrystalline
Can be obtained by:Can be obtained by:- Microwave plasma
enhanced CVD- Laser ablation of graphite
Results: spsp33 hybridisationhybridisation øø10 10 ÷÷ 50 nm
nodules of 50 nm nodules of diamond diamond nanocrystalline
filmsnanocrystalline films smoother surfacesmoother surface11÷÷3 3
μμm thick, 80 GPa hardness, low friction coefficientm thick, 80 GPa
hardness, low friction coefficient
-
VIZ GRAF, Busteni, October 2006 21
Multifunctionalisation Multifunctionalisation through
nanoporesthrough nanopores
Nanopore creationNanopore creation new properties, keeping / new
properties, keeping / enhancing the initial ones enhancing the
initial ones multifunctionalisationmultifunctionalisationCore
material+nanoporesCore material+nanopores nanostructured
nanostructured
materialmaterialNanopores creation :Nanopores creation :--
nanoporous Carbon structuresnanoporous Carbon structures-- ceramic
nanoporous materialsceramic nanoporous materials
Nanoporous Nanoporous Carbon Carbon
structuresstructuresNanoporous carbon + Metal particles
Nanoporous carbon + Metal particles catalyst materials*catalyst
materials*
*L. Gray et al., Wiley, 2005.
-
VIZ GRAF, Busteni, October 2006 22
BCNs infiltrationBCNs infiltration bulk nanocomposite
materialsbulk nanocomposite materialsProcessed by solProcessed by
sol--gel method in the gel method in the ““aeroaero--gelgel””
variantvariant
Ceramic nanoporous materialsCeramic nanoporous materialsBlock
ceramic materials (BCNs) Block ceramic materials (BCNs)
Nanostructured ceramic membranes (NCMs)Nanostructured ceramic
membranes (NCMs)Commonly made from SiO2, Al2O3, TiO2 and ZrO2
- pores diameter: 3÷ 5 nm
Processing by Aerogel methodProcessing by Aerogel methodlike
block nanoporous ceramicslike block nanoporous ceramics
Producing by SelfProducing by Self--assembly assembly method
method templatetemplate--assisted assisted
selfself--assemblyassembly like biological systemslike biological
systems
-
VIZ GRAF, Busteni, October 2006 23
SuperconductiveSuperconductiveceramicsceramics
Ionic conductive ceramicsIonic conductive ceramics
Ionic carriers transport Ionic carriers transport by diffusionby
diffusionNernst Nernst –– Einstein equation:Einstein equation:
σi = Di . Ni . Qi / k . T- σi electrical conductivity- Di
diffusion coefficient of “ i ” specie- Qi electrical charge- Ni
charge carrier concentration- k Boltzman constant
- T absolute temperature
σi = ƒ(Di)
-
VIZ GRAF, Busteni, October 2006 24
Electrical SuperconductiveElectrical SuperconductiveCeramics by
Grain Boundary ControlCeramics by Grain Boundary
ControlDigb>> Div σigb >> σiv
Ionic superconductive ceramicsIonic superconductive
ceramicsSi3N4 / E2O - Al2O3- SiO2
(E = Na, Li, K, etc) MgO / Na2O - Al2O3- SiO2
Electronic superconductive ceramicsElectronic superconductive
ceramicsZrO2 / V2O5 - Bi2O3 - CuO AlN / YN, etc.
GB conduction
mainly at hightemperature
GB + latticeconduction
at roomtemperature
-
VIZ GRAF, Busteni, October 2006 25
Ionic superconductiveIonic superconductiveceramicsceramics
~ 5 x 102 at 1000 0C107Mullite / Na2O-Al2O3-SiO2
~ 102 at 1000˚C106~107 at 100˚CDMgO / Na2O-Al2O3-SiO2
~ 5 x 101 at 1000 0C107~ 108 at 100 0C1010Si3N4 /
Li2O-Al2O3-SiO2
~ 8 x 101 at 1000 0C107~ 107 at 100 0C1010Si3N4 /
Na2O-Al2O3-SiO2
Resistivity [Ω.cm-1]NanocompositeMonolithMaterial
Ionic conductive
-
VIZ GRAF, Busteni, October 2006 26
ConductivPass-way
Electronic grain boundary Electronic grain boundary conduction
in ceramicsconduction in ceramics
500nm
AlN
AlN
Grain boundary phase
AlN
Grain boundary phaseAlN
Electronic conductivity through pass-way of grain boundaries
Schematic model of conduction in Schematic model of conduction
in AlN/Y2O3AlN/Y2O3--CeO2CeO2nanoconanocompositesmposites
-
VIZ GRAF, Busteni, October 2006 27
Electronic superconductiveElectronic
superconductiveceramicsceramics
~10-1 at T1014Y-TZP/CNT
~108 at R T1012Al2O3 / TZP+CNT Hybrid
~ 10-1 at RT (AC) 1010Si3N4 / V2O5 System
~ 2 x10-1 at RT1011AlN / YN System
~ 102 at RT1014Y-TZP / Organic System
~ 102 at RT1014Y-TZP / Bi2O3-CuO-V2O5
Resistivity [Ω.cm-1]NanocompositeMonolithMaterial
Electronic conductive
-
VIZ GRAF, Busteni, October 2006 28
Polymer electricalPolymer
electricalmultifunctionalisationmultifunctionalisation
Purpose :Purpose :To get higher conductivity than common To get
higher conductivity than common
conductive polymers & higher strengthconductive polymers
& higher strength-- by high conductive metal particles by high
conductive metal particles
(Cu, Ag, Au) fillers (Cu, Ag, Au) fillers percolation threshold
percolation threshold controlled / unidirectional
conductioncontrolled / unidirectional conduction
To get special properties To get special properties magnetic
(e.g. nano Ni filler), magnetic (e.g. nano Ni filler), electronic,
optical,electronic, optical,shape memory effectsshape memory
effects
-
VIZ GRAF, Busteni, October 2006 29
Shape memory effect inShape memory effect innanocomposite
polymersnanocomposite polymers(artificial muscles(artificial
muscles))
Ionic PolymerIonic Polymer-- metal nanocompositesmetal
nanocomposites- Elecyroactive polymers per fluorinated ionomers
Polyperfluoroethilenesulfonate, e.g. Nafion, Fluolon etc.
-- Applied electric field Applied electric field generation
generation of cations of cations migration toward cathod migration
toward cathod
pressure pressure reversible bending reversible bending 10 x
higher than shape memory 10 x higher than shape memory alloys (e.g.
Nialon)alloys (e.g. Nialon)
Mechanism :Mechanism :
Applications:Applications: actuators, medical devices etc.
-
VIZ GRAF, Busteni, October 2006 30
ElectricalElectricalmultifunctionalisation
multifunctionalisation of materials with CNTsof materials with
CNTs
Electrical/electronic properties of CNTsElectrical/electronic
properties of CNTs- One dimensionalityOne dimensionality 1 D space
1 D space electrons confined electrons confined
in one direction in one direction ideal 1 D conductors /
semiconductors ideal 1 D conductors / semiconductors ƒƒ (cyrality
(cyrality –– atom disposal in the hexagonal ray)atom disposal in
the hexagonal ray)
-- BendingBending atom disposal changes cylarity change metal to
semiconductor transitions nanojunctionsnanojunctions
Field Emission Transistors
- Monochromatic electron beams, emitters, nanoconnectors
etc.
-
VIZ GRAF, Busteni, October 2006 31
ElectronicElectronicmultifunctionalisation
multifunctionalisation by nanostructured coatingsby nanostructured
coatingsNanocrystalline diamond coatings
Fotoluminiscence Fotoluminiscence propertiesproperties
Colors depending on Colors depending on the electron beam the
electron beam intensity intensity easy to be easy to be
changedchanged
High resolution, high High resolution, high dimensions
displayersdimensions displayers
-
VIZ GRAF, Busteni, October 2006 32
OpticalOpticalmultifunctionalisationmultifunctionalisation
Strong transparent Si3N4Control the chemical composition and
structure of G.B.Control the chemical composition and structure of
G.B.Able to fabricate by common sintering processAble to fabricate
by common sintering processHigh strength and toughnessHigh strength
and toughness
400 mm 500 mm 600 mmApplications: Spatial vehicles windows
-
VIZ GRAF, Busteni, October 2006 33
Future trendsFuture trends
Nanocomposites
Strongly improvedmechanical properties
Ceramic/Ceramic SystemsCeramic/Ceramic Systems
Structural Materials
Nano Particle
Micro Matrix
Molecular Composites
Modified Lattice
Matrix Atom
Extremely low fraction of 2nd phases
(5 vol%, 0,01 − 0,1 vol%)Ceramic/Ceramic, Organic/Ceramic/
Ceramic/Ceramic, Organic/Ceramic/
Systems
Multifunctional Materials
Layer by LayerLayer by LayerLattices CompositesLattices
Composites
≈ 1 nm(Insulators)
1 μm
Bulk multilayer structure materialCeramic/Ceramic
SystemsCeramic/Ceramic Systems
Core/Shell NanoclusterComposites
Core
20 nm
Shell
Novel magnetic/electric properties
Metal/Metal, Metal/CeramicSystems
Magnetic/Optic/Electric Devices
Nanoporous Composites
2nd Phase
20 nm
MatrixNanopore
Large surface area, Improved thermal shock
resistance
Ceramic/Metal SystemsCeramic/Metal Systems
Catalysts, Coating Materials
NanoParticles
FullereneDispersed
NanoComposites
Nano Tubes
Self-Organized
NanoComposites
In-grain toughening
5 ÷ 10 nm(Ferroelectrics)
-
VIZ GRAF, Busteni, October 2006 34
ConclusionsConclusionsNanocomposite Nanocomposite materials open
materials open
an enormous potential for :an enormous potential for :- existing
materials multifunctionalisation- enhancing natural performances
of
existing materials- creation of new multifunctional materials-
materials designmaterials design- development of
functionally-graded
materials - broad and exciting research area
-
VIZ GRAF, Busteni, October 2006 35
Thank you for your attention !Thank you for your attention !