On the peculiarities of electrical conductivity in ARC plasma containing stainless steel and tungsten
The influence of stainless steel and tungsten impurities on the electrical conductivity of multicomponent arc plasma is considered in the ambient atmosphere of argon and air. The calculations are carried out on the base of Grad’s method, and it is shown that a small amount of metal causes the esse...
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| Datum: | 2018 |
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Національний науковий центр «Харківський фізико-технічний інститут» НАН України
2018
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| Zitieren: | On the peculiarities of electrical conductivity in ARC plasma containing stainless steel and tungsten / P.V. Porytskyy // Вопросы атомной науки и техники. — 2018. — № 6. — С. 249-251. — Бібліогр.: 8 назв. — англ. |
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| author | Porytskyy, P.V. |
| author_facet | Porytskyy, P.V. |
| citation_txt | On the peculiarities of electrical conductivity in ARC plasma containing stainless steel and tungsten / P.V. Porytskyy // Вопросы атомной науки и техники. — 2018. — № 6. — С. 249-251. — Бібліогр.: 8 назв. — англ. |
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| container_title | Вопросы атомной науки и техники |
| description | The influence of stainless steel and tungsten impurities on the electrical conductivity of multicomponent arc
plasma is considered in the ambient atmosphere of argon and air. The calculations are carried out on the base of
Grad’s method, and it is shown that a small amount of metal causes the essential changes in the values of electrical
conductivity in comparison with the case of pure gaseous mixtures. It is revealed that the increasing of metal
concentration leads to the decreasing of electrical conductivity under the certain conditions in arc plasmas.
Розглянуто вплив домішок нержавіючої сталі та вольфраму на електричну провідність
багатокомпонентної електродугової плазми в атмосфері сумішей аргону та повітря. Проведені розрахунки
ґрунтувалися на методі моментів Ґреда. Показано, що невелика кількість металевих домішок може суттєво
змінити величину коефіцієнта електричної провідності порівняно із випадком чистого аргону або повітря.
Виявлена можливість зменшення електричної провідності внаслідок збільшення концентрації вольфраму
або нержавіючої сталі в плазмовій суміші.
Рассмотрено влияние примесей нержавеющей стали и вольфрама на электрическую проводимость
многокомпонентной электродуговой плазмы в атмосфере смесей аргона и воздуха. Проведенные расчеты
основывались на методе моментов Грэда. Показано, что незначительное количество примесей металла
может существенно изменить величину коэффициента электрической проводимости в сравнении со
случаем чистого аргона или воздуха. Выявлена возможность уменьшения электрической проводимости
вследствие увеличения концентрации вольфрама или нержавеющей стали в плазменной смеси.
|
| first_indexed | 2025-11-27T21:27:53Z |
| format | Article |
| fulltext |
ISSN 1562-6016. ВАНТ. 2018. №6(118)
PROBLEMS OF ATOMIC SCIENCE AND TECHNOLOGY. 2018, № 6. Series: Plasma Physics (118), p. 249-251. 249
ON THE PECULIARITIES OF ELECTRICAL CONDUCTIVITY IN ARC
PLASMA CONTAINING STAINLESS STEEL AND TUNGSTEN
P.V. Porytskyy
Institute for Nuclear Research, Kyiv, Ukraine
E-mail: poryts@kinr.kiev.ua
The influence of stainless steel and tungsten impurities on the electrical conductivity of multicomponent arc
plasma is considered in the ambient atmosphere of argon and air. The calculations are carried out on the base of
Grad’s method, and it is shown that a small amount of metal causes the essential changes in the values of electrical
conductivity in comparison with the case of pure gaseous mixtures. It is revealed that the increasing of metal
concentration leads to the decreasing of electrical conductivity under the certain conditions in arc plasmas.
PACS: 52.25.Fi, 52.25.Vy, 52.25.Ya, 52.27.Cm, 52.77.Fv, 52.50.Nr, 52.80.Mg
INTRODUCTION
Arc plasma is often used in metallurgical applications
such as plasma etching, spraying, cutting and welding.
The presence of metallic vapors is widely observed in
arc plasma. Stainless steel and tungsten is widely used in
plasma devices and industrial electronic plants.
Sometimes they are doped with other materials to lower the
work function of the cathode material. At operation the
process of erosion leads to the evaporation of the metal
impurities into the discharge region that causes the change
of plasma properties.
The improvement in controlling plasma processing
needs for accurate numerical modeling. Transport
properties are indispensable input data for the modeling.
At weakly ionization the Lorentzian theory is suitable to
calculate the properties of multicomponent thermal
plasma [1]. But at increasing of ionization processes a
number of collision processes are known to be included
into consideration. Because of that it is the many
processes are needed to take into account in the
calculation procedure.
In this paper, the electrical conductivity for
multicomponent plasma with stainless steel and tungsten
impurities is calculated on the base of the Grad’s
method [2, 3]. It is shown that the impurities have an
influence on the transport properties of thermal plasma.
The influence of stainless steel and tungsten impurities
on the electrical conductivity of arc plasma is
considered in the ambient atmosphere of argon and air.
The increasing of metal concentration in discharge
plasma are known to be lead to the corresponding
increasing of electrical conductivity due to the low
value of ionization potential of metal. However, for the
case of tungsten and stainless steel components it is the
decreasing of electrical conductivity takes place. That
phenomenon caused by the shape resonance under the
collision of electron with neutral atom.
1. METHOD OF CALCULATION
It should be noted that the present state of the
theory of gas mixtures, as well as multicomponent
plasma, is characterized by the lack of a unified
approach to the description of transport processes. The
reason for this is a very complex nature of
dependencies of the properties of gas mixtures and
plasma on the properties of pure gases and
concentrations of the components.
It should be underlined that, now, the Grad’s method
of moments [2, 3] is an unique alternative in spite of the
most developed Chapman-Enskog’ method [4-8] to
solve the kinetic Boltzmann equation. Both the methods
are based on the formalism of Chapman-Cowling kinetic
integrals
2
1 2
2 3
0
2
llr rkT
e Q d
, (1)
where k is Boltzmann constant, T is temperature,
is a reduced mass of collided species of
and ,
1 2
2kT g , g is the relative
velocity, and transport cross-section of order l is
determined as
0
2 , 1 cos sinl lQ g g d
,
where is scattering angle, ,g is differential
scattering cross-section.
In the 13-moments (13M) approximation of the
Grad’s method the translational transport coefficients
are calculated as the sum of effective coefficients for
each species. The effective coefficients are calculated on
the base of combination of the Chapman-Cowling
integrals (2.1).
The studies of electronic transport coefficients are
known to need using of higher approximations. In that
way for electrical conductivity , can be write [3] as
1 2
2 23 2
2
e
e
q
n e
m kT q
. (2)
Here em is the mass of electron, en is electronic
density, the elements of determinants
nkp and
nkq are
the functions of the above pointed Chapman-Cowling
integrals. Script “ ‘ ” denotes the absence of elements
with indexes 0 and 1 (see for details [3-8]).
Others coefficients are calculated according to the
Lorentzian theory [2].
250 ISSN 1562-6016. ВАНТ. 2018. №6(118)
2. RESULTS AND DISCUSSION
The calculations are carried out at assumption of
local thermodynamic equilibrium. The following species
have been taken into account for argon-based mixtures:
e-, Ar, Ar+, Me, Me+, Me2+, Me2, Me2
+ and others
analogous mixtures. In turn, for air-based mixtures the
following species had used that’s are e-, N2,O2,NO, N, O,
N+, O+, NO+, N2
+, O2
+, Me, Me+, Me2+, Me2, Me2
+.
Where Me denotes the metal component.
The results of calculations for the case of nickel are
shown in Figs. 1-5.
F
ig. 1. Electrical conductivity of thermal plasma ( p =1 atm)
for pure argon and the equimolar mixtures of argon with
tungsten. Curves 1 ‒ Ar (this work calculations); 2 ‒ Ar –W
(99.9:0.1); 3 ‒ Ar –W (95:5);
4 ‒ Ar-W (90:10); 5 ‒ Ar (data from [8])
Fig. 2. Electrical conductivity of thermal plasma
( p =1 atm) for pure air and the equimolar mixtures of
air with tungsten. Curves 1 ‒ pure air (this work
calculations); 2 ‒ air –W (99:1); 3 ‒ air –W (95:5);
4 ‒ air –W (70:30); 5 ‒ air –W (50:50)
The obtained values are in a good agreement with the data
obtained by Chapman-Enskog method (Fig. 1). The
peculiarity of the Grad’ method is that the values have the
same dimensions at all of stages in calculation procedure due
to the control of calculation procedure may be improved.
It should be noted that under scattering of electrons on
argon the Ramsauer effect takes place that is determined
the properties of pure argon. However this influence can
be neutralized by metal additions in plasma.
Also, one can see that the appearance of tungsten
impurities causes the essential changing of electrical
conductivity coefficient with comparison to the case of
pure argon. That is needed to take into account under
studies of discharges with tungsten electrodes.
Let’s increase the concentration of tungsten in
mixture. One can see (Fig. 2) that in dense vapor the
electrical conductivity may be drop down under the
temperature growth.
A similar picture takes place in the case of the
mixture of components of stainless steel in mixture
(Figs. 3-5).
Fig. 3. Electrical conductivity of thermal plasma
( p =1 atm) for pure air and the equimolar mixtures of
air with iron. Curves 1 ‒ air (this work calculations);
2 ‒ air –Fe (99.9:0.1); 3 ‒ air –Fe (95:5);
4 ‒ air-Fe (90:10)
Fig. 4. Electrical conductivity of thermal plasma
( p =1 atm) for pure air and the equimolar mixtures of
air with iron. Curves 1 ‒ air (this work calculations);
2 ‒ air-Fe (99:1); 3 ‒ air -Fe (90:10); 4 ‒ air-Fe
(70:30); 5 ‒ air-Fe (50-50)
Fig. 5. Electrical conductivity of thermal plasma
( p =1 atm) for pure air and the equimolar mixtures of
air with stainless steel. Curves 1-air (this work
calculations); 2- air-Fe-Mo (99.9:0.5:0.5);
3- air-Fe-Mo (95:2.5:2.5); 4-air-Fe-Mo (90:5:5);
5- air-Fe-Mo (70-20-10)
ISSN 1562-6016. ВАНТ. 2018. №6(118) 251
The increasing of metal concentration in discharge
plasma are known to be lead to the corresponding
increasing of electrical conductivity due to the low
value of ionization potential of metal. However, for the
case of tungsten and stainless steel components it is the
decreasing of electrical conductivity takes place. This
phenomenon caused by the shape resonance under the
collision of electron with neutral atom. It should be
pointed that the observed decreasing of electrical
conductivity takes place in the mixtures of metal with
ambient gas only. In pure metal vapors that effect has
not realized.
Thus, it is needed the three following conditions to
appear the decreasing of electrical conductivity in arc
plasmas. They are the high concentration of metal, the
ambient gas, and the presence of a shape resonance for
electron-atom collisions.
CONCLUSIONS
Thus, a small amount of tungsten or stainless
impurities causes the essential changes in the value of
electrical conductivity coefficient of arc plasma in
comparison with the case of pure argon or air.
The calculations of electrical conductivity on the
base of Grad’s method have a good agreement with the
recent calculations based on Chapman-Enskog method.
The influence of the Ramsauer effect on the transport
coefficients can be neutralized by metal additions in
plasma.
Also, it is shown that in the case of plasma mixture
containing stainless steel and tungsten the electrical
conductivity may be drop down in dense metal vapors.
In other words, that is the increasing of metal
concentration leads to the decreasing of electrical
conductivity under the certain conditions in arc plasmas.
This effect takes place in the multicomponent plasma
mixtures only.
REFERENCES
1. P. Porytsky, I. Krivtsun, V. Demchenko, U. Reisgen,
O. Mokrov, A. Zabirov. On the application of the theory
of Lorentzian plasma to calculation of transport
properties of multicomponent arc plasmas // European
Phys. Journ. D. 2010, v. 57, № 1, p. 77-85.
2. H. Grad. On the kinetic theory of rarefied gases //
Comm. Pure and Appl. Math. 1949, v. 2, p. 331-407.
3. V.M. Zhdanov. Transport Processes in
Multicomponent Plasma. NY: “Taylor&Francis”, 2002.
4. S. Chapman, T.G. Cowling. The mathematical Theory
of Nonuniform Gases / 3rd Ed. Cambridge: “Cambbrige
University Press”, 1970.
5. J.H. Ferziger, H.G. Kaper. Mathematical theory of
transport processes in gases. Amsterdam: “North-
Holland”, 1972.
6. R.S. Devoto. Transport properties of Ionized
Monatomic Gases // Phys. Fluids. 1966, v. 9, № 6,
p. 1230-1240.
7. R.S. Devoto. Simplified Expressions for the
Transport Properties of Ionized Monatomic Gases //
Phys. Fluids. 1967, v. 10, № 10, p. 2105-2112.
8. R.S. Devoto. Transport coefficients of ionized
argon // Phys. Fluids. 1973, v. 16, № 5, p. 2105-2112.
Article received 12.09.2018
ОБ ОСОБЕННОСТЯХ ЭЛЕКТРИЧЕСКОЙ ПРОВОДИМОСТИ В ДУГОВОЙ ПЛАЗМЕ,
СОДЕРЖАЩЕЙ НЕРЖАВЕЮЩУЮ СТАЛЬ И ВОЛЬФРАМ
П.В. Порицкий
Рассмотрено влияние примесей нержавеющей стали и вольфрама на электрическую проводимость
многокомпонентной электродуговой плазмы в атмосфере смесей аргона и воздуха. Проведенные расчеты
основывались на методе моментов Грэда. Показано, что незначительное количество примесей металла
может существенно изменить величину коэффициента электрической проводимости в сравнении со
случаем чистого аргона или воздуха. Выявлена возможность уменьшения электрической проводимости
вследствие увеличения концентрации вольфрама или нержавеющей стали в плазменной смеси.
ПРО ОСОБЛИВОСТІ ЕЛЕКТРИЧНОЇ ПРОВІДНОСТІ В ДУГОВІЙ ПЛАЗМІ,
ЩО МІСТИТЬ НЕРЖАВІЮЧУ СТАЛЬ ТА ВОЛЬФРАМ
П.В. Порицький
Розглянуто вплив домішок нержавіючої сталі та вольфраму на електричну провідність
багатокомпонентної електродугової плазми в атмосфері сумішей аргону та повітря. Проведені розрахунки
ґрунтувалися на методі моментів Ґреда. Показано, що невелика кількість металевих домішок може суттєво
змінити величину коефіцієнта електричної провідності порівняно із випадком чистого аргону або повітря.
Виявлена можливість зменшення електричної провідності внаслідок збільшення концентрації вольфраму
або нержавіючої сталі в плазмовій суміші.
|
| id | nasplib_isofts_kiev_ua-123456789-149061 |
| institution | Digital Library of Periodicals of National Academy of Sciences of Ukraine |
| issn | 1562-6016 |
| language | English |
| last_indexed | 2025-11-27T21:27:53Z |
| publishDate | 2018 |
| publisher | Національний науковий центр «Харківський фізико-технічний інститут» НАН України |
| record_format | dspace |
| spelling | Porytskyy, P.V. 2019-02-19T15:02:04Z 2019-02-19T15:02:04Z 2018 On the peculiarities of electrical conductivity in ARC plasma containing stainless steel and tungsten / P.V. Porytskyy // Вопросы атомной науки и техники. — 2018. — № 6. — С. 249-251. — Бібліогр.: 8 назв. — англ. 1562-6016 PACS: 52.25.Fi, 52.25.Vy, 52.25.Ya, 52.27.Cm, 52.77.Fv, 52.50.Nr, 52.80.Mg https://nasplib.isofts.kiev.ua/handle/123456789/149061 The influence of stainless steel and tungsten impurities on the electrical conductivity of multicomponent arc plasma is considered in the ambient atmosphere of argon and air. The calculations are carried out on the base of Grad’s method, and it is shown that a small amount of metal causes the essential changes in the values of electrical conductivity in comparison with the case of pure gaseous mixtures. It is revealed that the increasing of metal concentration leads to the decreasing of electrical conductivity under the certain conditions in arc plasmas. Розглянуто вплив домішок нержавіючої сталі та вольфраму на електричну провідність багатокомпонентної електродугової плазми в атмосфері сумішей аргону та повітря. Проведені розрахунки ґрунтувалися на методі моментів Ґреда. Показано, що невелика кількість металевих домішок може суттєво змінити величину коефіцієнта електричної провідності порівняно із випадком чистого аргону або повітря. Виявлена можливість зменшення електричної провідності внаслідок збільшення концентрації вольфраму або нержавіючої сталі в плазмовій суміші. Рассмотрено влияние примесей нержавеющей стали и вольфрама на электрическую проводимость многокомпонентной электродуговой плазмы в атмосфере смесей аргона и воздуха. Проведенные расчеты основывались на методе моментов Грэда. Показано, что незначительное количество примесей металла может существенно изменить величину коэффициента электрической проводимости в сравнении со случаем чистого аргона или воздуха. Выявлена возможность уменьшения электрической проводимости вследствие увеличения концентрации вольфрама или нержавеющей стали в плазменной смеси. en Національний науковий центр «Харківський фізико-технічний інститут» НАН України Вопросы атомной науки и техники Низкотемпературная плазма и плазменные технологии On the peculiarities of electrical conductivity in ARC plasma containing stainless steel and tungsten Про особливості електричної провідності в дуговій плазмі, що містить нержавіючу сталь та вольфрам Об особенностях электрической проводимости в дуговой плазме, содержащей нержавеющую сталь и вольфрам Article published earlier |
| spellingShingle | On the peculiarities of electrical conductivity in ARC plasma containing stainless steel and tungsten Porytskyy, P.V. Низкотемпературная плазма и плазменные технологии |
| title | On the peculiarities of electrical conductivity in ARC plasma containing stainless steel and tungsten |
| title_alt | Про особливості електричної провідності в дуговій плазмі, що містить нержавіючу сталь та вольфрам Об особенностях электрической проводимости в дуговой плазме, содержащей нержавеющую сталь и вольфрам |
| title_full | On the peculiarities of electrical conductivity in ARC plasma containing stainless steel and tungsten |
| title_fullStr | On the peculiarities of electrical conductivity in ARC plasma containing stainless steel and tungsten |
| title_full_unstemmed | On the peculiarities of electrical conductivity in ARC plasma containing stainless steel and tungsten |
| title_short | On the peculiarities of electrical conductivity in ARC plasma containing stainless steel and tungsten |
| title_sort | on the peculiarities of electrical conductivity in arc plasma containing stainless steel and tungsten |
| topic | Низкотемпературная плазма и плазменные технологии |
| topic_facet | Низкотемпературная плазма и плазменные технологии |
| url | https://nasplib.isofts.kiev.ua/handle/123456789/149061 |
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