Modifications of aluminum film caused by micro-plasmoids and plasma spots in the effluent of an argon non-equilibrium plasma jet

Engelhardt, Max; Ries, Stefan; Hermanns, Patrick; Bibinov, Nikita; Awakowicz, Peter

doi:10.1088/1361-6463/aa802f

Cited by 12 publications

(50 citation statements)

References 42 publications

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“…This value is considerably lower than the magnetic field on the plasma spots axis assumed in [55] to explain the observed substrate damages. This difference can be caused by diamagnetic properties of the plasma plume, which is not in contact to the conductive wall under GAP plasma conditions.…”

Section: Discussionmentioning

confidence: 63%

“…Up to now the magnetic field of plasma spots is not direct established because of the stochastically temporal and spatial behavior, very small dimension and short lifetime of these plasma objects under DBD-like plasma jet conditions. There is, however, some indirect evidence of a magnetic field, i.e., the contraction of the plasma channel up to a current density of 10 7 -10 8 A•cm -2 and an extraction of paramagnetic atoms (aluminum, oxygen) from the treated substrate (aluminum film on the glass substrate) [55].…”

Section: Discussionmentioning

confidence: 99%

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Characterization of a nitrogen gliding arc plasmatron using optical emission spectroscopy and high-speed camera

Gröger¹,

Ramakers²,

Hamme³

et al. 2018

J. Phys. D: Appl. Phys.

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A gliding arc plasmatron (GAP), which is very promising for purification and gas conversion, is characterized in nitrogen using optical emission spectroscopy and high-speed photography, because the cross sections of electron impact excitation of N 2 are well known. The gas temperature (of about 5500 K), the electron density (up to 1.5×10 15 cm-3) and the reduced electric field (of about 37 Td) are determined using an absolutely calibrated intensified charge-coupled device (ICCD) camera, equipped with an in-house made optical arrangement for simultaneous two-wavelength diagnostics, adapted to the transient behavior of a gliding arc (GA) channel in turbulent gas flow. The intensities of nitrogen molecular emission bands, N 2 (C-B,0-0) as well as N 2 + (B-X,0-0), are measured simultaneously. The electron density and the reduced electric field are determined at a spatial resolution of 30 µm, using numerical simulation and measured emission intensities, applying the Abel inversion of the ICCD images. The temporal behavior of the GA plasma channel and the formation of plasma plumes are studied using a high-speed camera. Based on the determined plasma parameters, we suggest that the plasma plume formation is due to the magnetization of electrons in the plasma channel of the GAP by an axial magnetic field in the plasma vortex.

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Section: Discussionmentioning

confidence: 63%

Section: Discussionmentioning

confidence: 99%

Characterization of a nitrogen gliding arc plasmatron using optical emission spectroscopy and high-speed camera

Gröger¹,

Ramakers²,

Hamme³

et al. 2018

J. Phys. D: Appl. Phys.

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“…The dimension, form and erosion rate of those traces are comparable to the traces of cold cathode spot cores [8,9]. But, at the same time, gas and solid surface temperatures in [7] were considerably lower than the melting point of aluminum. Moreover, no lines of metal atoms were observed in emission spectra of plasma spots, which was interpreted in [7] as evidence that metal was not vaporized in that short time frame (about 100 ns) and low discharge current (about 0.1 A).…”

Section: Introductionmentioning

confidence: 66%

“…A common basis of all models that describe the properties of cathode spots, is local heating that causes thermionic electron emission, melting and vaporization of the cathode material [5,6]. In this respect, results presented in [7] show that a lot of physical properties regarding plasma spots are still unresolved. After a short treatment time (about 100 ns) of aluminum film on a glass surface from a dielectric barrier discharge (DBD)-like plasma jet operated in argon flow, different erosion traces of plasma spots are observed.…”

Section: Introductionmentioning

confidence: 99%

Formation and behaviour of plasma spots on the surface of titanium film

Hermanns¹,

Kogelheide²,

Bracht³

et al. 2020

J. Phys. D: Appl. Phys.

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Numerous studies have shown that dielectric barrier discharge (DBD) and DBD-like plasma jets interact with a treated surface in a complex manner. Eroded traces after treatment cannot be explained by conventional plasma-surface interaction theory. The mechanisms of a controlled formation of these plasma objects is still unclear. In this work, the authors show that the formation rate and characteristics of eroded traces, treating a titanium surface, can be controlled by process design and the combination of materials used. A thin (0.45 µm) layer of titanium film is deposited onto a glass substrate and is then treated in the effluent of a non-equilibrium atmospheric pressure plasma jet (N-APPJ) operated with argon or krypton flow. Plasma spots with diameters ranging from 100-700 µm are observed using an intensified digital camera on the titanium film surface. These plasma objects are strongly inhomogeneous, forming a core with a very high current density and leave erosion holes with diameters of about 1 µm. By using krypton as a working gas, effective erosion of the titanium substrate can be shown, whereas by using argon no traces are detected. For the latter case, traces can be provoked by deposition of a thin aluminum layer on top of the titanium substrate, by creation of artificial scratches or by an additional swirling flow around the discharge. Based on the experimental results presented in this and previous papers, it is assumed that plasma spots with dense cores are produced by an interaction of micro-vortices within the plasma channel and by the formation of an extremely high axial magnetic field. This assumption is confirmed by destruction of the treated surface material, extraction of paramagnetic atoms and toroidal substrate heating, which is most likely caused by a helical current of the plasma spot.

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“…The jet contains the chemically active particles that provide a basis for different applications, such as the modification of the surfaces [23][24][25][26][27] and the treatment of the biological objects [2,[28][29][30] to which the jet is directed. There are also investigations on generation of the nitrogen oxides in the discharges in airflow [17,31,32].…”

Section: Introductionmentioning

confidence: 99%

Nonsteady-state processes in a low-current discharge in airflow and formation of a plasma jet

et al. 2019

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The paper describes the investigations of a low-current discharge in airflow with the electrode configuration of coaxial plasmatron. An inner diameter of the plasmatron nozzle is of 0.5 cm and the mass airflow rate is from 0.1 to 0.3 g s −1 . Typical averaged discharge current is varied from 0.06 to 0.2 A. In these conditions, due to airflow the so-called plasma jet forms in the plasmatron nozzle and at its exit. The total current in plasmatron mainly flows via the constricted plasma column of the glow discharge and only a small fraction of current is carried by the jet. The principal idea of the experiments is to reveal the mechanism of the jet formation and to elucidate how the nonsteady discharge regimes influence on the jet properties. We have proposed the method for the jet diagnostics, which is based on measuring the currents to the additional diagnostic electrodes located outside the nozzle. The obtained data show that the jet current forms due to electrons that are emitted from the boundary of plasma column. The temporal behavior of the jet current is determined by the position of the column inside the plasmatron nozzle, which changes with time. Hence, the term 'plasma jet' has to be used with care, since the charged particles in the jet area are the electrons. The estimated electron density in the jet is of about 10 9 cm -3 .

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Modifications of aluminum film caused by micro-plasmoids and plasma spots in the effluent of an argon non-equilibrium plasma jet

Cited by 12 publications

References 42 publications

Characterization of a nitrogen gliding arc plasmatron using optical emission spectroscopy and high-speed camera

Characterization of a nitrogen gliding arc plasmatron using optical emission spectroscopy and high-speed camera

Formation and behaviour of plasma spots on the surface of titanium film

Nonsteady-state processes in a low-current discharge in airflow and formation of a plasma jet

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