Program: ,,CEEX”
Authority:
Contract No. 89/2006; Project type: P-CD
Project Title: „Production
and behavior’s study of C, W and Be coatings used for thermonuclear fusion
installations’ first wall”
Code: FUSITERMAT
Period: 24 months (October 2006 – September 2008)
Project Director: Dr. Cristian P. LUNGU
Coordinator: National Institute of Laser, Plasma and Radiation Physics
(INFLPR), Bucharest-Magurele
(CO/P1), www.inflpr.ro
Partners:
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Partner 2 |
“Horia Hulubei" National Institute for Physics and
Nuclear Engineering, |
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Project
Responsible: Diplom. Physicist Ion VATA |
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Partner 3 |
National |
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Project
Responsible: Dr Mihai Florin LAZARESCU |
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Partner 4 |
“Politehnica”
University, (BIOMAT) Bucuresti, www.biomat.ro |
|
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Project
Responsible: Dr. ing.Florin
MICULESCU |
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Partner 5 |
SC MEDAPTEH SRL, Com. N. Balcescu, Jud. Bacau |
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Project
Responsible: Ing. Valentin MIDONI |
We propose to use the high vacuum deposition method for
the deposition of Be, W and C on substrates of W, CFC, inconel and copper. The original
Thermionic Vacuum Arc (TVA) method, developed at NILPRP assures high purity,
high energies for the ions (which can be varied) of the materials to be
deposited, very good adherence between the substrate and the as deposited films.
There will be also used the possibility of simultaneous
depositions of Be and Cu in order to improve beryllium’s quality regarding the
hardness and its adaptability to the copper substrate.
On tungsten and CFC substrates there will be deposited
different thickness of Be and C – from 1 nm to 10 nm – in order to simulate the
interactions from the reactor’s main chamber and to analyze their
inter-diffusion at the contact area.
On the copper substrate there will be co-deposited Be
and Cu (in different concentrations) in order to form a 20 nm buffer layer.
After reaching the thickness of 20 nm for the buffer layer the beryllium
deposition process will continue in order to achieve a beryllium film’s
thickness of 8 μm to 10 μm. The so formed structure will be analyzed
in order to study the properties’ changing (especially adherence) as a function
of the Be/Cu concentration ratios in the buffer layer.
All depositions will be made using different Be, C, W
and Cu ions’ energies necessary to study and to understand the influence of
this parameter over the interface between the substrate and the film tacking
into account that this parameter couldn’t be studied in the case of classical
deposition techniques like thermal evaporation, cathode sputtering or even the
vacuum arc.
On the samples obtained using TVA technology will be
experimented the following treatments (similar to the phenomena expected to
happen in the fusion reactor):
·
post deposition thermal treatments in the temperature range
of 100ºC - 500ºC necessary for the study of the inter-diffusion between
beryllium and tungsten on one hand and carbon and tungsten on the other
·
prolonged deuterium discharges necessary to estimate
beryllium’s erosion rate as a function of deposition parameters (especially
beryllium ions’ energies used in the TVA deposition process)
Measurable goals:
·
The erosion rate of deposited layers (using both TVA and
thermal evaporation methods) exposed to deuterium plasma. During the exposure
to the deuterium plasma the samples will be heated to temperatures between
100ºC - 500ºC in order to simulate the fusion reactor’s conditions. We will
compare the samples obtained using TVA technique with the ones obtained using
thermal evaporation. We expect to have a lower sputtering rate for the samples
obtained using our technology
·
RBS analysis of the interface layer between Be and W in
order to detect the Be-W compounds (Be22W, Be12W, and Be2W)
and to determine the diffusion beryllium depth profiles into the tungsten
substrate. The study of the interface layer is of great interest because it is
known that alloying the beryllium with tungsten will decrease the melting point
of the structure
·
The adherence of beryllium films on a copper substrate as a
function of its ions’ energies which will be varied in the range of 100 eV –
600 eV
·
The adherence of beryllium films on a copper substrate
having a Be-Cu compound as a buffer layer (obtained by simultaneous deposition
of Be and Cu) as a function of the Be/Cu concentrations’ ratio. In this stage
we will also test the adherence after post deposition thermal treatments in the
temperature range of 0ºC - 500ºC
·
The study of the interface layer formed between carbon and
tungsten. It is known, as we described above, that at the interface area, a
tungsten carbide layer appears which induce changes into the structure
The deposited and treated layers will be with respect
to the composition, structure, gaseous retention, interdiffusion at the contact
of the two layers, by XPS, AFM, SEM, RBS. We will measure the adherence degree
by exposing them to tear weights, the thermal conductivity coefficient by
measuring the caloric flux that passes through them
Proposed
targets/dead lines
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I: Fitting out the slot needed
for starting off the project’s fundamental research activities. Studies
regarding the influence of irradiations with neutrons and deuterons of the W,
C and Be films deposited onto substrates made of the main candidate materials
for the fusion reaction chamber (W, CFC, Cu, inconel, etc). |
15.11.2006 |
|
II:
Be film depositions having thickness of 10- 50 nm onto tungsten, carbon, inconel,
copper. The study of the influence of Be ions’ bombardment and of temperature
over the Be-W and Be-C compounds and
over layer interdiffusion.. |
30.06.2007 |
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III.
Carbon thin films depositions having thickness of 10- 50 nm onto tungsten, inconel, copper at
ionic energies between 200 and 500 eV, thermal treatment of the films, study
of carbon ion influence on the formation of composites C-Me (Me= W, inconel,
Cu) and interdiffusion. |
15.12.2007 |
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IV:
Tungsten films depositions having thickness of 10- 50 nm onto Be, inconel, copper at ionic
energies between 200 and 500 eV, thermal treatment of the films, study of
tungsten ion influence on the formation of composites W-Be, W-inconel, W-Cu
and inetrdifussion |
30.06.2008 |
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V: Be
films depositions having thickness of
8-10 µm onto inconel and copper with a intermediate layer. Study of
the adherence, by sticking a device in order to measure the adherence by
adding weights. (Pulling test). |
30.09.2008 |
Output:
Preparation in
the laboratory conditions of the composite films that can be resulted after
activities in the nuclear fusion reactors and studies of the related phenomena.
Dissemination: scientific publications, conferences, website
Fulfilled
targets:
Equipment acquisition: Partial payment of a stabilized dc supply (1-5kV,
0-2A) from Heinzinger
Electronic
Publications:
•
Conferences:
•
Oral presentation on the International Confernce “PROGRESS OF CRYOGENICS AND ISOTOPES SEPARATION”, Calimanesti-Caciulata,
Beryllium film formation by thermionic vacuum arc and thermal evaporation
authors: C. P.
Lungu*, I. Mustata*, V. Zaroschi*, A. M. Lungu*,
P. Chiru*, A. Anghel*, G. Burcea**,
V. Bailescu**, G. Dinuta**, F. Din**, *National
Institute for Lasers, Plasma and Radiation Physics, **Nuclear Fuel Factory, Pitesti, Romania