3.4.2.2.1. PLASMA PROCESSING*

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National Institute for Aerospace Researches Elie
Carafoli - INCAS SA, Bucharest 220, Iuliu Maniu,
Sect 6, Bucharest, Phone[phone],
Fax[phone] web www.incas.ro, e-mail
incas_at_aero.incas.ro
INCAS
Interest in FP 6 call 'Nanotechnologies and
nanosciences, knowledge-based multifunctional
materials and new production processes and
devices FP6-2004-NMP-TI-4
3.4.2.2.1. PLASMA PROCESSING
The fundamental characteristics of plasma process
are represented by the assured flame temperature
, about 15000 Celsius degrees, jet speed about
300 m/s, layer porosity about 2. The main
parameters of the plasma process are sketched as
follows

• Plasma parameters
• Air dilution
• Gas composition
• Plasma jet temperature
• Speed

• Powder
• Distribution,size, grain shape
• Spray speed distribution
• Staying time in plasma

• Flame
• Flame speed
• Spraying distance

• Under layer
• Temperature
• Residual tension control
• Particle impact speed

• Nozzle
• Flow gas
• Powder flow

In connection with 3.4.2.2. TECHNOLOGIES
ASSOCIATED WITH THE PRODUCTION, TRANSFORMATION
AND PROCESSING OF KNOWLEDGE-BASED MULTIFUNCTIONAL
MATERIALS
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Table 1 The potential application of the plasma
coatings

• - high potential
• - industrial application
• or in progress of
• introducing
• - in progress of development
• Without symbol unexplored potential

1 anticorrosive protections 2 anti wear
protections 3 electronic proprieties 4
radiation 5 chemical/biological proprieties
6 ended form 7 restore 8 powder
processing 9 sensitive composite 10
unstable materials 11 amorphous coatings
trough solidification
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• The process limits are specially determined by
  the reduced adherence between metal support and
• bonding layers, high porosity and partial
  oxidation of the particles.
• Fundamental problems to be solved in our opinion
  by the research in the field are represents by
  the
• Plasma generator power increase
• Powder flow speed increase
• Comparable study of the condition by air
  pressure environment about layers porosity,
  structure modification , deposition part
• Realisation for management of the technological
  process, especial for ceramic layers of a relax
• structure with deliberate accomplished porosity
  and micro cracks
• Computerised metallography and electronic
  microscopy investigations regarding the interface
  aspects, support - adherence layer - external
  layers and dynamic of the modifications induced
  by different mechanic and thermal stresses.
• Within the consortium, in connection with this
  theme, INCAS is able to participate in the
  activities associated to the last two paragraphs.

Fig. 1 Plasma jet installation
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National Institute for Aerospace Researches Elie
Carafoli - INCAS SA, Bucharest 220, Iuliu Maniu,
Sect 6, Bucharest, Phone[phone],
Fax[phone] web www.incas.ro, e-mail
incas_at_aero.incas.ro
INCAS
3.4.2.2.3. MULTIFUNCTIONAL CERAMIC THIN FILMS
WITH RADICALLY NEW PROPERTIES
INCAS have the experience to achieve some duplex,
triplex layers, FGM - functionally graded
materials, ceramics for industrial proposed
especial for hot parts of turbojet, for some
metallurgy parts, power industry, etc. The aimed
parts are stressed at erosive, corrosive wear,
thermal shock, sliding friction, which can work
simultaneously at high values. The ceramic
layers unanimous utilized, generally partial
stabilized zirconia base, have as main servitude,
the major difference between thermal expansion
coefficients values of ceramic layers and
metallic support during thermal shock and
associated induced internal stressed. To
decrease the thermal shock effect on the ceramic
layers, multilayered structures, FGM, etc. are
utilized. Each intermediate layer composition is
graded between external layers (internal and
external). A progress in this domain, is
represented by the recent experimental studies
performed by Lewis Research Center, Cleveland,
Ohio, for plasma sprayed coatings. An improved
bond coat, incorporating metallic or ceramic and
cermets layers has been demonstrated to increase
the thermal fatigue life of a plasma sprayed TBC
by a factor of two or more. Utilizing this
system, the second layer of the bond coat
incorporates a fine dispersion of a particulate
second phase in a MeCrAlY matrix. The second
phase is required to have a coefficient of
thermal expansion as low as possible or
preferable lower than yttrium zirconium layer and
it must be stable up to intended temperature,
chemically inert with respect to the MeCrAlY
matrix and must be chemically compatible with
the thermal grown alumina scale.
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INCAS has in progress evaluation experiments of
the triplex layer type MeCrAlY/MeCrAlY 90
Al2O3 10/ZrO2. Y2O3 obtained by plasma spray
technology . The achievement of some thin layers
impose the CVD, PVD, Sputtering, etc.
technologies .
Fig. 2 Ceramic and bonding layers, SEM imagine
Fig. 3 Zr associate distribution
Within the consortium, in this direction, INCAS
is able to participate especially in the
achievement of some multifunctional layers ,
thermal shock stressed .
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National Institute for Aerospace Researches Elie
Carafoli - INCAS SA, Bucharest 220, Iuliu Maniu,
Sect 6, Bucharest, Phone[phone],
Fax[phone] web www.incas.ro, e-mail
incas_at_aero.incas.ro
INCAS
Quick thermal shock test installation for
multifunctional ceramic coatings

• Protection layers and especial ceramics have
  main servitude lower resistance at thermal
  shock.
• For aeronautical application, rockets,
  metallurgical, power industries, is important the
  behavior of
• this coatings in limited functional conditions -
  with additionally requests.
• Thermal shock classical installation mentioned
  in literature have heating
• cooling cycle with substantial low speed than
  extreme functional conditions. In the same
• context are not testing methods in extreme
  condition, unanimous accepted.
• The main characteristics of the proposed thermal
  shock installation
• testing sample dimensions-rectangle LxWxH mm -
  25x25x2or circular ?25x12 mm
• the test specimen materials metals, alloys,
  composite materials, ceramic materials, coatings
• (enamel, multilayered, TBC, FGM, etc.)
• maximum testing temperature 1400 degrees
  Celsius
• heating time from the environment temperature
  till the testing temperature15150 sec
• cooling time from the testing temperature till
  the environment temperature15 250 sec
• temperature speed measurement 150 ms
• sample view during the test
• temperatures measurement during all the time test
• samples photo in the heating and cooling areas
• samples lighting in the heating and cooling
  areas
• manual cycle

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• work parameters registration
• - environment temperature
• - oven temperature
• - sample temperature
• - heating time
• - cooling time
• - cycle working time
• - graphic and table display of samples
  temperatures against time and position during the
  test
• This installation is absolutely necessary, in
  our opinion, for testing and selection
• of the ceramic layers in extreme functional
  condition, for industrial applications.
• INCAS is able to conceive, design and achieve (in
  cooperation with European partners) quick
  thermal shock installation for ceramic layers by
  FGM type.

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National Institute for Aerospace Researches Elie
Carafoli - INCAS SA, Bucharest 220, Iuliu Maniu,
Sect 6, Bucharest, Phone[phone],
Fax[phone] web www.incas.ro, e-mail
incas_at_aero.incas.ro
INCAS
3.4.2.3.1.1. Nanocomposites epoxy-Montmorillonite
Nanocomposites are a new class of advanced,
nanometer-scale multiphase polymer composites
that often display many enhanced physical
properties strength, hardness, thermal and
viscoelastic properties. Nanocomposites are
synthesized by dispersing expholiated clays,
nanometer particle and aggregates into a polymer
matrix (epoxy) or by infiltrating epoxy into the
interlayer structure of layered silicates. INCAS
in cooperation with ICECHIM Bucharest develop
researches regarding nanocomposites epoxy-
Montmorillonite (aluminum hydrate silicate), via
second way. In the first stage some samples of
epoxy resin as such and epoxy-10 Montmorillonite
(weight) are performed. The mechanical testing
results up to date are synthesized in table 2.
Table no. 2 Epoxy resin characteristics with and
without Montmorillonite
No. Sample Tensile Strength MPa Young Module E MPa Hardness Shore
1 Epoxy LY 554 110 28 000 75
2 Epoxy LY 55410 Montmorillonite 120-130 52 000 83
It is to notice the significant effect of the
Montmorillonite addition upon the elasticity
modulus. The researches will be continued with
complementary studies regard nanocomposites-epoxy-
glass fiber, nano epoxy-fibers composites and
maybe nano epoxy-carbonnanotube, incorporated..
In connection with 3.4.2.3. ENGINEERING SUPPORT
FOR MATERIALS DEVELOPMENT, 3.4.2.3.1. MATERIALS
BY DESIGN MULTIFUNCTIONAL ORGANIC MATERIALS
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National Institute for Aerospace Researches Elie
Carafoli - INCAS SA, Bucharest 220, Iuliu Maniu,
Sect 6, Bucharest, Phone[phone],
Fax[phone] web www.incas.ro, e-mail
incas_at_aero.incas.ro
INCAS
3.4.3.1.1.1. Carbon carbon composites
nano-ceramic matrix
Carbon fiber and carbon-carbon was first
developed for aerospace technology (component in
missiles, reentry vehicles, in space shuttles as
structural parts and as brake lining and brake
disc material for civil and military
aircraft). Materials and Tribology Department of
INCAS realized performing carbon fiber (PAN
precursor) and carbon-carbon composites, phenolic
matrix. In fig. 4 and Fig. 5 the Debyegram of PAN
precursor and thermooxidate PAN are presented.
Intensity diminution of peak diffraction points
out adequate PAN stabilization.
Fig. 4 PAN Debyegram
Fig. 5 Debyegram of the thermooxidate PAN
3.4.3.1. DEVELOPMENT OF NEW PROCESSES AND
FLEXIBLE, INTELLIGENT MANUFACTURING SYSTEMS
3.4.3.1.1. NEW PRODUCTION TECHNOLOGIES FOR NEW
MICRO-DEVICES USING ULTRA PRECISION ENGINEERING
TECHNIQUES
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Some characteristics of FC obtained are
synthesized in table 3.
Table 3
Characteristics of FC
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In fig. 8 and fig. 9 are point out the effects
of thermal treatment upon density and mechanical
characteristics of the C-C composites.

• Recently researches report on C-C composites and
  nano C-C composites as brake materials.
• The main features of C-C as friction materials
  for aircraft brakes are
• a great ablation heat (20.000 Kcal/Kg)
• specific weight 1,7 1,9 Kg/dm3
• friction coefficient 0,3
• dimensional stability at high temperatures
  (small dilatation coefficient, max 2x10-6
  v.s.10-5 for steel)

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• For concordance in tribological and antioxidant
  properties of C-C composites distinct solutions
  was
• developed
• FC - fiber (unidirectional 2D tissue, chopped,
  felt preform) and phenolic matrix with 25 CSi
  (reported
• to phenolic resin)
• Nanocomposites C-C ceramic matrix via so called
  LSI (Liquid Silicon Infiltration).
• The sol gel SiO2 (50 weight reported to phenolic
  resin) infiltrated in a C-C by thermal
  treatment
• at 1600C generate ceramic matrix (CSi). The
  results of tribological testing are presented in
  table no 5

Table 5 Friction coefficients for C-C composites
No. Material Friction coefficient
1 C-C composite 0,130,14
2 C-C25 C-Si composite 0,30,35
3 C-C50 SiO2 colloidal composite 0,30,35
In the future INCAS- Material and Tribology
Laboratory aims to achieve carbon fiber
composites ceramic matrix, via nanosilicium
carbide-mesophase, or to use polymeric precursor
(policarbosilane) for CSi matrix.