Transcript Document

R
INCAS
National Institute for Aerospace Researches “Elie Carafoli” - INCAS SA, Bucharest
220, Iuliu Maniu, Sect 6, Bucharest, Phone:004.021.434.00.83, Fax:004.021.434.00.82
web: www.incas.ro, e-mail: [email protected]
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
•Flame:
Flame speed
Spraying distance
•Nozzle:
Flow gas
Powder flow
 Powder:
Distribution,size, grain shape
Spray speed distribution
Staying time in plasma
 Under layer
Temperature
Residual tension control
Particle impact speed
* In connection with 3.4.2.2. TECHNOLOGIES ASSOCIATED WITH THE PRODUCTION, TRANSFORMATION AND
PROCESSING OF KNOWLEDGE-BASED MULTIFUNCTIONAL MATERIALS
Table 1 The potential application of the plasma coatings
Industry
Function of coatings
1
2
Chemical


Power

Space and aeronautical

3
4
5

7
8
9
10
11






o
o

6
o


o

Nuclear
o
Medicine
o
Metallurgy
Materials technology






o
 - high
potential
• - industrial
application
or in progress of
introducing
o - in progress of
development
Without symbol
– unexplored
potential


o
o
o
o

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
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
R
INCAS
National Institute for Aerospace Researches “Elie Carafoli” - INCAS SA, Bucharest
220, Iuliu Maniu, Sect 6, Bucharest, Phone:004.021.434.00.83, Fax:004.021.434.00.82
web: www.incas.ro, e-mail: [email protected]
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.
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 .
R
INCAS
National Institute for Aerospace Researches “Elie Carafoli” - INCAS SA, Bucharest
220, Iuliu Maniu, Sect 6, Bucharest, Phone:004.021.434.00.83, Fax:004.021.434.00.82
web: www.incas.ro, e-mail: [email protected]
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} - 25x25x2;or circular 25x1÷2 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 temperature:15÷150 sec
•cooling time from the testing temperature till the environment temperature:15 ÷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
•automatic cycle
•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.
R
INCAS
National Institute for Aerospace Researches “Elie Carafoli” - INCAS SA, Bucharest
220, Iuliu Maniu, Sect 6, Bucharest, Phone:004.021.434.00.83, Fax:004.021.434.00.82
web: www.incas.ro, e-mail: [email protected]
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 epoxyMontmorillonite (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
Sample
No.
1
Epoxy LY 554
2
Epoxy LY
554+10%
Montmorillonite
Tensile
Strength
[MPa]
Young Module
E
[MPa]
Hardness
[Shore]
110
28 000
75
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
R
INCAS
National Institute for Aerospace Researches “Elie Carafoli” - INCAS SA, Bucharest
220, Iuliu Maniu, Sect 6, Bucharest, Phone:004.021.434.00.83, Fax:004.021.434.00.82
web: www.incas.ro, e-mail: [email protected]
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
Some characteristics of FC obtained are synthesized in table 3.
Table 3
Characteristics of FC
Tensile strength
[MPa]
3,1x103
E, Young
modulus
[MPa]
2.4x105
Table 4
No.
1
2
3
4
Fibre diametre
[milimicroni]
%C
Process out put
7
98.5
50%
Mechanical and tribologies characteristics
Material
CF – 2D tissue composite
CF – Uni directional composite
Chopped FC (3.5 mm)
composites
C-C composites 2D tissue
Tensile stregth
[MPa]
750
850
300÷350
Friction
coefficient
0.13
0.13
0.13
200÷250
0.13
In fig. 8 and fig. 9 are point out the effects of thermal treatment upon density and mechanical
characteristics of the C-C composites.
Fig.8 Tensile strength variation during
Fig.9 Density variation during thermal
thermal treatment of C-C composites
treatment of 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)
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 1600°C generate ceramic matrix (CSi). The results of tribological testing are presented in table no 5:
Table 5
Friction coefficients for C-C composites
Material
Friction
coefficient
1
C-C composite
0,13÷0,14
2
C-C+25% C-Si composite
0,3÷0,35
3
C-C+50% SiO2 colloidal
composite
0,3÷0,35
No.
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.