Influence of plasma treatment on erosion haracteristics and structure of reversible hydrogen getters
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| Cite this: | Influence of plasma treatment on erosion haracteristics and structure of reversible hydrogen getters / V.N. Borisko, V.V. Bobkov, V.V. Chebotarev, I.E. Garkusha, M.V. Lototsky, N.S. Poltavtsev, I.A. Rudaya, Yu.F. Shmal’ko, R.I. Starovojtov, V.I. Tereshin, O.V. Byrka // Вопросы атомной науки и техники. — 2000. — № 6. — С. 166-168. — Бібліогр.: 7 назв. — англ. |
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Borisko, V.N. Bobkov, V.V. Chebotarev, V.V. Garkusha, I.E. Lototsky, M.V. Poltavtsev, N.S. Rudaya, I.A. Shmal’ko, Yu.F. Starovojtov, R.I. Tereshin, V.I. Byrka, O.V. 2015-03-18T19:25:16Z 2015-03-18T19:25:16Z 2000 Influence of plasma treatment on erosion haracteristics and structure of reversible hydrogen getters / V.N. Borisko, V.V. Bobkov, V.V. Chebotarev, I.E. Garkusha, M.V. Lototsky, N.S. Poltavtsev, I.A. Rudaya, Yu.F. Shmal’ko, R.I. Starovojtov, V.I. Tereshin, O.V. Byrka // Вопросы атомной науки и техники. — 2000. — № 6. — С. 166-168. — Бібліогр.: 7 назв. — англ. 1562-6016 https://nasplib.isofts.kiev.ua/handle/123456789/78563 533.9 en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Low temperature plasma and plasma technologies Influence of plasma treatment on erosion haracteristics and structure of reversible hydrogen getters Article published earlier |
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Influence of plasma treatment on erosion haracteristics and structure of reversible hydrogen getters |
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Influence of plasma treatment on erosion haracteristics and structure of reversible hydrogen getters Borisko, V.N. Bobkov, V.V. Chebotarev, V.V. Garkusha, I.E. Lototsky, M.V. Poltavtsev, N.S. Rudaya, I.A. Shmal’ko, Yu.F. Starovojtov, R.I. Tereshin, V.I. Byrka, O.V. Low temperature plasma and plasma technologies |
| title_short |
Influence of plasma treatment on erosion haracteristics and structure of reversible hydrogen getters |
| title_full |
Influence of plasma treatment on erosion haracteristics and structure of reversible hydrogen getters |
| title_fullStr |
Influence of plasma treatment on erosion haracteristics and structure of reversible hydrogen getters |
| title_full_unstemmed |
Influence of plasma treatment on erosion haracteristics and structure of reversible hydrogen getters |
| title_sort |
influence of plasma treatment on erosion haracteristics and structure of reversible hydrogen getters |
| author |
Borisko, V.N. Bobkov, V.V. Chebotarev, V.V. Garkusha, I.E. Lototsky, M.V. Poltavtsev, N.S. Rudaya, I.A. Shmal’ko, Yu.F. Starovojtov, R.I. Tereshin, V.I. Byrka, O.V. |
| author_facet |
Borisko, V.N. Bobkov, V.V. Chebotarev, V.V. Garkusha, I.E. Lototsky, M.V. Poltavtsev, N.S. Rudaya, I.A. Shmal’ko, Yu.F. Starovojtov, R.I. Tereshin, V.I. Byrka, O.V. |
| topic |
Low temperature plasma and plasma technologies |
| topic_facet |
Low temperature plasma and plasma technologies |
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2000 |
| language |
English |
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Вопросы атомной науки и техники |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
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Article |
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1562-6016 |
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https://nasplib.isofts.kiev.ua/handle/123456789/78563 |
| citation_txt |
Influence of plasma treatment on erosion haracteristics and structure of reversible hydrogen getters / V.N. Borisko, V.V. Bobkov, V.V. Chebotarev, I.E. Garkusha, M.V. Lototsky, N.S. Poltavtsev, I.A. Rudaya, Yu.F. Shmal’ko, R.I. Starovojtov, V.I. Tereshin, O.V. Byrka // Вопросы атомной науки и техники. — 2000. — № 6. — С. 166-168. — Бібліогр.: 7 назв. — англ. |
| work_keys_str_mv |
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2025-11-26T15:08:48Z |
| last_indexed |
2025-11-26T15:08:48Z |
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1850625770157768704 |
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UDC 533.9
166 Problems of Atomic Science and Technology. 2000. № 6. Series: Plasma Physics (6). p. 166-168
INFLUENCE OF PLASMA TREATMENT ON EROSION
HARACTERISTICS AND STRUCTURE
OF REVERSIBLE HYDROGEN GETTERS
V.N. Borisko, V.V. Bobkov, V.V. Chebotarev*, I.E. Garkusha*, M.V. Lototsky***,
N.S. Poltavtsev**, I.A. Rudaya, Yu.F. Shmal’ko**, R.I. Starovojtov,
V.I. Tereshin*, O.V. Byrka*
Kharkov National University, 61022, Svobody sq. 4, Kharkov,
* Institute of Plasma Physics of the NSC KIPT, 61108, Akademicheskaya str. 1, Kharkov,
** Institute of Solid State Physics, Materials and Technology of the NSC KIPT
*** Institute of Mechanical Engineering of National Academy of Sciences of Ukraine
Introduction
In the paper [1] an analysis of bombardment of
cathodes of gas discharge devices with high-energy
plasma particles was carried out. Those cathodes were
manufactured on the base of reversible low-pressure
getters of hydrogen. It was shown that bombardment of
the cathodes by particles stimulated the hydrogen
desorption from the surface. In this case the quantity of
stripped hydrogen, resulted due to both a thermal
decomposition of hydride phases and an ion stimulated
desorption, was proportional to the flux of incident
particles. In that way the internal feedback between
energy flux to the electrode surface and intensity of
gassing was provided. In other words, a protective gas-
dynamic target was formed close to the surface of the
reversible sorbents of hydrogen. This target essentially
decreased the sputtering yield of a material. Such
systems could be used for high hydrogen concentration
buildup in the plasma facing materials. As it was shown
in work [2], there is a possibility of decreasing the
carbon erosion due to the hydrogen shielding. This
shielding effect arises as the result of accumulation of
high dose of hydrogen at near surface layers of material
during special regime of high-flux hydrogen ion
bombardment. But it is not clear whether such
mechanism can be realized when using intermetallides
and metals. So, it was of a great interest to consider the
possible mechanisms of high hydrogen content buildup
in such systems.
In this work the results of investigations of plasma
processing of Zr55V40Fe5 alloy, modified by 3% of B2O3
and preliminary saturated by hydrogen, are discussed.
Experimental results and discussion
The specified above material with additional binding
dopant (copper powder in quantity 40 % from total
weight of a composite) was pressed under the room
temperature. The pressure of pressing and duration of
composite exposure under the pressure were about 0.3
GPa and 5 minutes accordingly. The sample of pressed
composite had a form of cylinder of 20 mm in diameter
and 5 mm in thickness Total content of hydrogen
accumulated in the sample was 2,5 dm3.
Pulsed nitrogen plasma streams processing was used
for modeling the material behavior under high power
heat load. The duration of plasma stream generation was
(3-5) µs. The ion energy was 2 keV, plasma density ~
2x1014 cm-3, specific power of plasma stream up to 10
MW/cm2, and plasma energy density varied in the range
of (10-30) J/cm2.
It was shown that treatment by pulsed plasma
streams with specific power value, similar to one
expected for disruption process in tokamak-reactor, led
to melting of surface layer and significant weight losses
of processed sample (up to 0.53 mg/cm2 per pulse).
Electron microscope images of the sample surface,
obtained before and after plasma irradiation, are
presented in Fig. 1.
After bombardment of samples with 7 pulses the
phase analysis of both sample surfaces, irradiated by
plasma and non-irradiated, was carried out. The analysis
was carried out by difractometer DRON-2 with use the
Cu-Kα radiation. The registration of diffraction picture
was performed in an interval of Bragg angles 2θ = 20-
150o in a mode of continuous record on a plotter tape.
Obtained difractograms were scanned and translated
into a digital form under simultaneous corrective
actions for elimination of a background and drift of a
zero line. As a result the difractogram profiles were
obtained as pairs of values “Bragg angle 2θo (with step
in the reflex region 0,1o) - intensity Ie (mm)”.
Analysis of difractograms was carried out with use of
the specialized software with realizing the algorithm of
minimization of the divergence factor R [3], which
calculated by formula:
( )
∑
∑ −
= 2
2
eI
cIeI
R
, (1)
Here Ie, Ic - experimentally observed and calculated
intensities accordingly.
Calculated intensities Ic were approximated by
expression [4]:
∆
−−=
2
00 22exp θθ
cc II , (2)
Where Ic
0 and 2θ0 - calculated intensity and Bragg angle
of maximum of peaks accordingly, ∆ - halfwidth of a
peak measured at the peak height where its intensity is
by e times lower than maximum one.
The calculated intensity of a maximum of jth peak of ith
phase was determined as:
( ) 00
ijiijc IWI = , (3)
Here Iij
0 - theoretical intensity of peak maximum, Wi -
weight factor that is proportional to the mass portion of
the ith phase (in the case of absence of the intensities
distortions).
The difractograms analysis was carried out on the
base of known models of material structure (definition
of the theoretical intensities Iij
0) with the help of the
software package "Crystal Structure Determination",
developed in the Lvov State University (the algorithms
of calculations are given in work [5]). Bragg angles
were obtained when taking into account the symmetry
and periods of phases lattice [3,4].
To provide the minimum value of factor R at the
process of calculations there was carried out the
adjustment of ∆ values (∆ was accepted identical to all
present phases) as well as the weight factors of intensity
Wi and periods of a lattice for each phase. Adjustment
was carried out with use of a simplex - method [6]. The
step of a computational grid at calculations of the factor
R from the expression (1) was 0,01o.
For difractograms assignment of indice the earlier
received data on the phase-structure and the hydrogen
sorption characteristics of hydride forming materials of
similar structure were used [7].
Characteristic of phases for both irradiated and non-
irradiated sides of a material sample, obtained as a result
of difractograms assignment of indice (Fig. 2,3) are
given in the Table 1. High values of the divergence
factors are caused, apparently, by distortions of lines
intensity due to texturing, which, as is known [2], can
achieve of dozens of times. At that, as it is possible to
see from the Fig. 2,3, the intensity of copper lines
considerably surpass the intensity of the lines of other
phases, that complicates the assignment of indice
additionally. Nevertheless, on the base of the completed
analysis it is possible to conclude the following.
The irradiation of a sample leads to appreciable (on
the level of 15 %) broadening of lines in difractogram
and simultaneous reduction of absolute intensities of
the lines. It testifies that sample side, irradiated by
pulsed plasma stream, has fine grained, and probably
partially amorphous structure. According to the data of
the electron microscopy, the pulsed plasma stream
treatment leads to melting the sample surface under a
condition of the barbotage of desorbed hydrogen
bubbles through the melt and subsequent its high speed
cooling after the plasma pulse action.
The periods of the copper lattice for both non-
irradiated and irradiated sides of the sample exceed the
appropriate reference data (0,3615 nm). Moreover, for
irradiated side the period is even higher. Probably, it is
caused both by an introduction of nitrogen from incident
plasma stream into a crystal lattice of copper and by its
subsequent diffusion to the depth of the sample.
The lattice periods of hydride forming intermetallic
phases, namely Laves phase λ2–Zr(V,Fe)2HX and phase
Zr3(V,Fe)3OHX, are higher than periods of initial
intermetallides (0,7396 nm and 1,2156 nm
respectively), but are lower than lattice periods of
completely saturated hydrides (0,7886 nm and 1,2656
nm). For irradiated side of sample the periods of a
lattice of these phases were appreciably decreased in
comparison with initial state. Comparison of the
obtained results (see Table) with the literature [5] allows
to estimate degree of saturation by hydrogen of a Laves
phase as 72 % before irradiation and 64 % after
irradiation. The data for the η–phase are 49%
Table. Phase content of the sample
Value Characteristic
Nonirradiated
side
Irradiated
side
Divergence factor R 0,458 0,528
Average halfwidth of peak, ∆, o 0,30 0,34
Lattice period,nm a=0,36187 a=0,36215
Wi 0,1256 0,08197 Cu
(F m 3m)
∑ i
i
W
W , %
76,21 64,21
Lattice period,nm a=0,77496 a=0,77110
Wi 0,02502 0,02186 λ2–
Zr(V,Fe)2HX
__________
15 µm
(F d 3 m)
∑ i
i
W
W , % 15,18 17,12
Lattice period,nm – a=0,70549
Wi – 0,01207 ZrCu5(HX)
(F 4 3 m)
∑ i
i
W
W , % – 9,95
Lattice period,nm a=0,3621
c=0,4469
a=0,3626
c=0,4552
Wi 0,01147 0,00546 ε–ZrHX
(I 4)
∑ i
i
W
W , % 6,96 4,28
Lattice period,nm a=1,23991 a=1,23152
Phase
(sym-
metry
group)
__________
15 µm
167
Wi 0,007534 0,00630 η–
Zr3(V,Fe)3OHX
(F d 3 m)
∑ i
i
W
W , % 4,57 4,93
Fig. 1. Images of the sample surface
before and after plasma treatment
and 30 % respectively. It testifies that intensive
desorption of a hydrogen from these hydride phases
takes place during bombardment. Besides, desorption of
hydrogen from zirconium hydride probably takes place
also. During a bombardment the weight factors of the
intensity of the Laves phase and the η-phase
(normalized to the sum of the weight factors of all
phases) vary unsignificantly. At the same time similar
parameter for a copper decreases as much as more than
10 %, and for a zirconium hydride it decrease by 1,5
times. At that a phase of ZrCu5 intermetallide with a
little bit increased period of a lattice in comparison with
the reference data (0,687 nm) appears in the irradiated
sample. It can be caused by introduction of hydrogen or
nitrogen atoms into material. The most probable
explanation of this fact is the interaction of zirconium
hydride with the melt of copper during a pulse of
plasma processing. The melting temperature of copper
is much lower in comparison with other components of
a composite. In result the ZrCu5 intermetallide of system
Zr – Cu, which is the most enriched by copper, is
formed during melt crystallization.
I, mm
40
168
Fig. 2 The difractogram of the non-treated sample and its fragments
Fig. 3 The difractogram of the treated sample and its fragments
References
[1] Ye. V. Klochko, et al. Int. J. Hydrogen Energy, 1999, vol.
24, pp. 169-174.
[2] E. Salonen et al. Physical Review B, (1999), v.60, No 20,
14005-14008
[3] G.H.W. Milburn. X-ray crystallography. Мoscow. Мir,
1975. p. 256 .
[4] L.M. Kovba, V.K. Trunov. Rentgenofazovyj analiz.
Moscow State University, 1976. p. 232 (in Russian).
[5] V.K. Pecharsky et al. Vestnik L’vovskogo Universiteta,
seria: khimiya, 1984, № 25, p. 9–11 (in Russian).
[6] K.Hartmann, E.Lezki, W.Schafer. Statistische
Versuchsplanung und-auswertung in der Stoffwirtschaft.
М.:Мir, 1977. p. 552.
[7] V.A. Yartys’, I.Yu. Zavalij, M.V. Lototsky.
Koordinatsionnaya khimiya, 1992, v.18, № 4, p.409–423 (in
Russian.
40 60 80 100 120
0
50
100
Cu
λ2-Zr(V,Fe)2Hx
ε-ZrHx
η-Zr3(V,Fe)3OHx
2 θθθθ, o
002
111
022 113
222
133 024
30 35 40
0
20 022
133 224
113
110
115
333
222
002
044
011
55 60 65 70
0
10
20
121
211
008
337
115
333 066
228
157
555
022266
013
044
357
248
466112
20 40 60 80 100 120 140
0
40
80
120
Cu
λ2-Zr(V,Fe)2Hx
ε-ZrHx
η-Zr3(V,Fe)3OHx
ZrCu5(Hx)
002
111
022 113
222
133
024
022
113
20 25 30 35 40
0
10
20
30
113
002 011
133
022 022
022
115
333
113
002
222
110
55 60 65 70
0
4
8
117
155
224
121
211
008
337
115
333
066
228
022
112
555
157
266
044
333
357
248013
76 78 80 82 84
0
4
8
12
044
220
177
339
0 2 10
268
159
377
2 2 10
Experimental results and discussion
Characteristic
Fig. 2 The difractogram of the non-treated sample and its fragments
Fig. 3 The difractogram of the treated sample and its fragments
References
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