Materiale electrotehnice noi

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Materiale electrotehnice noi

• Nanodielectrici

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Structura disciplinei
Capitolul Continutul
1 Fenomene in materialele electrotehnice 1.1. Conductia electrica 1.2. Polarizarea electrica 1.3. Magnetizarea materialelor 1.4. Pierderi in materialele electrotehnice
2 Materiale conductoare noi 2.1. Materiale conductoare clasice 2.2. Materiale supraconductoare 2.3. Conductori organici si nanotuburi de carbon 2.4. Materiale pentru realizarea de memristori 2.5. Aplicatii moderne ale materialelor conductoare
3 Materiale semiconductoare noi 3.1. Materiale semiconductoare clasice 3.2. Polimeri semiconductori 3.3. Materiale semiconductoare nanostructurate 3.4. Aplicatii moderne (celule solare, microprocesoare de inalta frecventa, ecrane TV, laseri)
4 Materiale dielectrice noi 4.1. Evolutia materialelor dielectrice 4.2. Straturi subtiri 4.3. Nanodielectrici 4.4. Oxizi metalici 4.5. Aplicatii
5 Materiale magnetice noi 5.1. Evolutia materialelor magnetice 5.2. Materiale magnetice amorfe 5.3. Materiale magnetice nanostructurate (nanocristaline, organice) 5.4. Fire si filme subtiri din materiale magnetice 5.5. Aplicatii moderne (miezuri magnetice, memorii, hard-discuri, carduri magnetice)
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Nanodielectrici

• Polymer nanocomposites as dielectrics
• Characterisation nanostructure, electrical
  mecanical properties, thermal stability
• Numerical modeling of nanodielectrics
• Possible applications of polymer nanocomposites
  in Electrical Engineering

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Nanodielectrici

• Polymer nanocomposites as dielectrics
• Characterisation nanostructure, electrical
  mecanical properties, thermal stability
• Numerical modeling of nanodielectrics
• Possible applications of polymer nanocomposites
  in Electrical Engineering

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• 1994 Symbolic birth of Nanodielectrics
• John Lewis published the paper Nanometric
  Dielectrics in
• IEEE Transactions on Dielectrics and Electrical
  Insulation
• Nanodielectrics Polymer nanocomposites with
  dielectric properties
• polymers (PA, PE, PP, PVC, epoxy resins,
  silicone rubbers)
• nano-fillers (LS, SiO2, TiO2, Al2O3)
• 1 to 100 nm in size,
• 1 to 10 wt in content
• homogeneously dispersed in the polymer
  matrix.
• 2002 First experimental data on nanometric
  dielectrics.
• 2002-2008 Articles in the field reported that
• nano-filler addition has the potential of
  improving the electrical, mechanical and thermal
  properties as compared to the neat polymers
• polymer nanocomposites are increasingly
  desirable as coatings, structural and packaging
  materials in automobile, civil, aerospace and
  electrical engineering.
• 2006-2008 Project CEEX- PoNaDIP

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Steps of the research
Characterization
Design Realizing
Structure-Property Relationship
Modeling
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Design realizing

• Research at UPB-ELMAT
• 14 combinations polymer nanofiller
• Plane samples 10 X 10 cm2, thickness 1 mm
• Nanofillers1 to 100 nm in size, 1 to 10 wt in
  content, and homogeneously dispersed in the
  polymer matrix

POLYMER thermoplastic thermoset
NANOFILLER organic inorganic
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Design realizing

• Nanocomposites investigated
• PP, PVC and LDPE with SiO2 nanoparticles of 15 nm
  diameter
• PP, PVC and LDPE with TiO2 nanoparticles of 15 nm
  diameter
• PP, PVC and LDPE with Al2O3 nanoparticles of 40
  nm diameter
• nanofillers content 2, 5 and 10 wt.
• Manufacturing by direct mixing method
• Samples for electrical tests plaques of square
  shape (10 x 10 cm2) having the thickness of 0.5
  mm.

Installation for nanocomposite manufacturing
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Nanodielectrici

• Polymer nanocomposites as dielectrics
• Characterisation nanostructure, electrical
  mecanical properties, thermal stability
• Numerical modeling of nanodielectrics
• Possible applications of polymer nanocomposites
  in Electrical Engineering

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Nanostructure SEM at ICECHIM
Characterization
LDPE - SiO2
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• Electrical properties
• Dielectric Spectroscopy at UPB/ELMAT
• real part of the permittivity ( )
• loss tangent (tan d)
• dielectric spectroscopy Novocontrol ALPHA-A
  Analyzer (3) in combination with an Active Sample
  Cell ZGS (4) and a Temperature Control System
  Novotherm (5)
• frequency range 10-3 106 Hz

Characterization
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Electrical properties Dielectric Spectroscopy at
UPB/ELMAT
Results for PP nanocomposites with Al2O3, SiO2
and TiO2 fillers at T 300 K
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Electrical properties Dielectric Spectroscopy at
UPB/ELMAT
Results for PVC nanocomposites with Al2O3, SiO2
and TiO2 fillers at T 300 K
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Electrical properties Dielectric Spectroscopy at
UPB/ELMAT
Results for LDPE nanocomposites with Al2O3, SiO2
and TiO2 fillers at T 300 K
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Electrical properties Dielectric Spectroscopy at
UPB/ELMAT
Results for LDPE - Al2O3 nanocomposites, for
different filler concentration, at T 300 K
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• Electrical properties
• Absorption-Resorption Currents at UPB/ELMAT
• Resistivity
• Keithley 6517 Electrometer in combination
  Keithley 8009 Test Fixture

Characterization
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Electrical properties Absorption-Resorption
Currents at UPB/ELMAT
Characterization
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Characterization
Electrical properties Resistivity of LDPE
nanocomposites at UPB/ELMAT
Material Relative volume resistivity at 10 V Relative volume reisistivity at 500 V
Unfilled LDPE 1 1
LDPE with 5 wt nano-SiO2 39.39 0.54
LDPE with 5 wt nano-Al2O3 6.08 0.19
LDPE with 5 wt nano-TiO2 4.09 0.72
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• Mechanical properties at ICECHIM
• LDPE SiO2 and LDPE Al2O3 nanocomposites
• According to ISO 527 on specimens type IB (5
  specimens for each test) with 50 mm/min for
  tensile strength and 2 mm/min for modulus of
  elasticity.

Characterization
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Nanodielectrici

• Polymer nanocomposites as dielectrics
• Characterisation nanostructure, electrical
  mecanical properties, thermal stability
• Numerical modeling of nanodielectrics
• Possible applications of polymer nanocomposites
  in Electrical Engineering

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Ideas multi-core model
(Tanaka)
Numerical model at UPB/ELMAT
Modeling
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Numerical model at UPB/ELMAT
3D Model

• Sample features
• thickness 1 mm
  - diameter of the nanoparticle 40 nm
  - thickness
  if the interface 10 nm
  
  - filler content 5
  - relative
  permittivities
  
• nanoparticle/interface/matrix 10/6/2.2

Modeling
interface
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Numerical model at UPB/ELMAT
Electrostatic field
div (e grad V) 0
V electric scalar potential e electric
permittivity
Modeling
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Numerical model at UPB/ELMAT
Computational domain in FLUX 3D

• Main data of the numerical model
• dimension of the elementary cube 120 nm along
  each axis
  - nanoparticle diameter 40 nm
• - thickness of the interface 10 nm
  
  - concentration
  of nanoparticles 5
• - relative electric permittivities
  
• nanoparticle/interface/matrix 10/6/2.2
  
  - applied voltage 0.02 V

Modeling
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Numerical model at UPB/ELMAT
Descretization mesh - finite element method

• Size of the mesh
• 6784 nodes
  - 41770 volume finite elements
• - tethrahedral elements

Modeling
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Numerical model at UPB/ELMAT
Computation of the equivalent permittivity
1) Computation of the electric energy stored in
the material samples

2) Computation of the capacitance
of the elementar capacitor by using two different
methods 3) Evaluation of the equivalent rel.
electric permittivity er eq
Modeling
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Numerical model at UPB/ELMAT
Numerical resultsElectric scalar potential
color map
Modeling
Without nanoparticles With
nanoparticles
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Numerical model at UPB/ELMAT
Numerical resultsElectric field strength color
map
Without nanoparticles With
nanoparticles
Modeling
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Numerical model at UPB/ELMAT
Parametric study

• filler content fc
• diameter of the nanoparticle dn
• thickness of the interface ti
• relative permittivity of the polymer matrix erm
• relative permittivity of the interface eri
• relative permittivity of the nanofiller ern

Modeling
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Numerical model at UPB/ELMAT
Numerical resultsequivalent permittivity vs.
interface permittivity
ere f(eri) fc 5 dn 40 nm ti 10 nm erm
2.2 ern 10 eri 3 4 5 6 7 8
Modeling
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Numerical model at UPB/ELMAT
Numerical resultsequivalent permittivity vs. the
thickness of the interface layer
ere f(ti) fc 5 dn 40 nm ti 5 10
15 20 nm rvi 0 erm 2.2 ern 10 eri 4
Modeling
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Numerical model at UPB/ELMAT
Numerical resultsequivalent permittivity vs. the
diameter ofthe nanoparticle
ere f(dn) fc 5 dn 10 20 30 40 50
nm ti 10 nm erm 2.2 ern 10 eri 4
Modeling
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Numerical model at UPB/ELMAT
Numerical resultsequivalent permittivity vs.
nanoparticle permittivity
ere f(ern) fc 5 dn 40 nm ti 10 nm erm
2.2 ern 4 10 eri 2.2
Modeling
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Numerical model at UPB/ELMAT
Particle agglomeration
Modeling
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Numerical model at UPB/ELMAT
Particle agglomeration isolated particles
Modeling
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Nanodielectrici

• Polymer nanocomposites as dielectrics
• Characterisation nanostructure, electrical
  mecanical properties, thermal stability
• Numerical modeling of nanodielectrics
• Possible applications of polymer nanocomposites
  in Electrical Engineering

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• Nanocomposite applications in Electrical
  engineering at ETN-EE
• Manufacturing and testing of coil holders
• Selected materials LDPE Al2O3 and LDPE SiO2
  with 2 filler content.
• Coil holders made from selected nanocomposites
  have better behaviour as compared with those from
  the neat polymer (dielectric strength, mecanical
  properties and, obviously, flame retardancy)