Untersuchungen zur Wandkonditionierung mit mikrowellenerzeugten Plasmen in einem toroidalen Magnetfeld

Für den Betrieb von Fusionsanlagen ist es erforderlich die Gefäßwände durch Abscheidung dünner, sauerstoffbindender Filme in reaktiven Gasen ($SiH_{4}$, $B_{2}H_{6}$) zu konditionieren und akkumulierte Verunreinigungen regelmäßig zu entfernen. Die Verwendung supraleitender Feldspulen an zukünftigen Experimenten erfordert Verfahren, die mit den permanenten Magnetfeldern kompatibel sind. In dieser Arbeit werden daher mikrowellenerzeugte Plasmen in einem toroidalen Magnetfeld untersucht. Dazu wird eine Charakterisierung der Entladung in Abhängigkeit von den wählbaren Parametern Magnetfeldstärke, Neutralgasdruck und Mikrowellenleistung in unterschiedlichen Prozessgasen durchgeführt. Die Abscheidung von Schichten erfolgte in Methan und Acetylen, wobei eine räumlich aufgelöste Untersuchung der Eigenschaften der Filme erfolgte. Die Abtragung der Schichten in $H_{2}$, $D_{2}$ und $O_{2}$-Plasmen wurde verglichen.For the operation of fusion devices it is essential to condition the vessel walls by deposition of thin oxygen gettering layers in reactive gases ($SiH_{4}$, $B_{2}H_{6}$) and to remove accumulated contaminations regularly. The usage of superconducting field coils in coming experiments requires methods which are compatible with the permanent magnetic fields. Therefor this thesis is dedicated to the investigation of microwave generated discharges in a toroidal magnetic field. The characterisation of the discharge is done in dependence on the magnetic field strength, neutral gas pressure and microwave input power for different process gases. For the deposition of layers in methane and acetylene the spatial distribution of the films and their characteristics have been investigated. On the other hand side the removal of the layers by $H_{2}$, $D_{2}$ and $O_{2}$ -plasmas is discussed

Untersuchungen zur Wandkonditionierung mit mikrowellenerzeugten Plasmen in einem toroidalen Magnetfeld

Für den Betrieb von Fusionsanlagen ist es erforderlich die Gefäßwände durch Abscheidung dünner, sauerstoffbindender Filme in reaktiven Gasen ($SiH_{4}$, $B_{2}H_{6}$) zu konditionieren und akkumulierte Verunreinigungen regelmäßig zu entfernen. Die Verwendung supraleitender Feldspulen an zukünftigen Experimenten erfordert Verfahren, die mit den permanenten Magnetfeldern kompatibel sind. In dieser Arbeit werden daher mikrowellenerzeugte Plasmen in einem toroidalen Magnetfeld untersucht. Dazu wird eine Charakterisierung der Entladung in Abhängigkeit von den wählbaren Parametern Magnetfeldstärke, Neutralgasdruck und Mikrowellenleistung in unterschiedlichen Prozessgasen durchgeführt. Die Abscheidung von Schichten erfolgte in Methan und Acetylen, wobei eine räumlich aufgelöste Untersuchung der Eigenschaften der Filme erfolgte. Die Abtragung der Schichten in $H_{2}$, $D_{2}$ und $O_{2}$-Plasmen wurde verglichen.For the operation of fusion devices it is essential to condition the vessel walls by deposition of thin oxygen gettering layers in reactive gases ($SiH_{4}$, $B_{2}H_{6}$) and to remove accumulated contaminations regularly. The usage of superconducting field coils in coming experiments requires methods which are compatible with the permanent magnetic fields. Therefor this thesis is dedicated to the investigation of microwave generated discharges in a toroidal magnetic field. The characterisation of the discharge is done in dependence on the magnetic field strength, neutral gas pressure and microwave input power for different process gases. For the deposition of layers in methane and acetylene the spatial distribution of the films and their characteristics have been investigated. On the other hand side the removal of the layers by $H_{2}$, $D_{2}$ and $O_{2}$ -plasmas is discussed

Treatment of Flax Fabric with AP-DBD in Parallel Plane Configuration

For the use of natural fibers in composite materials it is often necessary to improve the compatibility between fiber (sizing) and polymer matrix systems, e.g., by increasing the number of functional groups on the fiber surfaces. In this work, a dielectric barrier discharge (DBD) source in plane configuration is used to treat flax fabrics in ambient air. It is examined whether it is possible to increase the functionality on both fabric sides, which is achieved by simple changes in the DBD setup. After evaluating the treatment homogeneity of the filamentary plasma, an explanation for the treatment mechanism on the fiber surfaces is developed. It is shown that waxy substances, which naturally occur on natural fibers, play an important role in the wettability of the fabric

Improved adhesive bonding of CFRP due to re-deposition prevention during UVns-laser cleaning

Due to increasing demand for weight reduction, the use of carbon fiber-reinforced plastics (CFRPs) is steadily growing in the field of transportation like automotive and aircraft. An important method for joining these materials is adhesive bonding, which requires suitable surface conditions and therefore often an appropriate pre-treatment to provide high bond strength. In this context treatment with lasers, especially in the UV range, has been in scientific focus during the last years [1,2]. During the laser treatment, contaminations and the uppermost matrix layer will be ablated and thus are removed from the surface. Re-deposition of ablated material on the as-treated surface but also a too strong fiber exposure are critical problems, which can lead to deterioration of the adhesive strength. In this work the distribution of re-depositions generated by a nanosecond UV laser (λ = 248 nm) on EP based CFRP and the prevention of the corresponding re-deposition effects by parameter selection for a laser scanning process have been investigated. A possible strategy to reduce debris formation on the surface with adapted selection of pulse overlap with respect to laser fluence [3] will be presented and limits of laser pre-treatment, like a strong fiber exposure, will be discussed. Finally the UV laser treatment will be compared to other methods for adhesive pre-treatment like CO2-snow in combination with atmospheric pressure plasma and corundum blasting

Für einen Beschichtungsprozess vorbereitete Polyurethanoberfläche und Verfahren zu deren Herstellung

Die Erfindung betrifft ein Verfahren zur Herstellung eines Polyurethanformteiles, umfassend die Schritte Bereitstellen einer Reaktionsmischung, die zu Polyurethan reagieren kann, Bereitstellen einer Form zur Formgebung des Polyurethanformteiles mit einer niedrigen Oberflächenenergie und eines spezifischen Additiv für die Reaktionsmischung. Das Verfahren umfasst ferner die Schritte Mischen des Additiv mit der Reaktionsmischung und Aushärten dieser Mischung in der Form. Dabei gewährleistet das Additiv, das eine gute Enthaftung möglich ist, ohne dass Trennmittel eingesetzt werden müssen

Verfahren zur Herstellung eines Bauteilsmit einer Verbundsstruktur sowie mit dem Verfahren herstellbares Bauteil

Producing a component with a composite structure, comprises introducing at least one molded part (1) made of fiber composite material into a casting mold, providing a section of the molded part with a covering, and casting at least one section of the molded part with the metallic material in a casting process, or connecting at least one section of the molded part with the metallic material, providing the covering for the section of the molded part, introducing the covering in the casting mold, casting with the metallic material, and connecting the molded part with the covering. Producing a component with a composite structure made of a fiber composite material and a metallic material, comprises introducing at least one molded part (1) made of fiber composite material into a casting mold, providing a section of the molded part with an electrically insulating covering, prior to the casting process for preventing a contact of the fiber composite material with the metal material and connecting with the molded part and the metallic material in a positive- and/or force-fitting manner, and casting at least one section of the molded part with the metallic material in a casting process, or connecting at least one section of the molded part made of the fiber composite material with the metallic material, providing the electrically insulating covering at least for the section of the molded part, introducing the electrically insulating covering in the casting mold and casting with the metallic material in the casting process, and connecting the molded part with the electrically insulating covering, after the casting process. An independent claim is also included for the component comprising the composite structure made of the fiber composite material and the metallic material, where at least one section of the molded part is embedded in a matrix made of the metallic material and is separated by the electrically insulating covering from the metallic material

Implantatkörper mit Wirkstoffträgerschicht und Abgabekontrollschicht

The invention relates to an implant body comprising a substrate (3) and, on the surface thereof, a layer system consisting of an active substance carrier layer (2) and a release control layer (1) arranged on same, said active substance carrier layer having a plurality of open pores (4), and said release control layer (1) being a layer that is deposited from the gas phase and that reduces the area of the pore opening of the pores (4) of the active substance carrier layer (2) without closing them

Atmospheric pressure plasma activation of natural fibres for improved matrix interaction: Abstrac presented at 16th International Conference on Plasma Surface Engineering, 17.-21.09.2018, Garmisch-Partenkirchen

Several investigations have shown that plasma activation is a suitable, environmental friendly method to modify fibre materials. Depending on the plasma chemistry, the surface energy and also the topography of fibres can be significantly changed which can lead to an improved wettability and surface chemistry. This is of particular interest during subsequent processing steps if fibres are implemented into fibre-reinforced polymers (FRPs).The processing of natural fibres is particularly difficult because their surface chemistry and topography are highly inhomogeneous and depend on the natural growth of the fibres. Additionally, the chemistry of cellulose, hemicellulose, pectin and lignin is not compatible with a lot of matrix systems. One possibility to improve the adhesion between natural fibres and matrix systems is to treat the fibres with cold plasma at atmospheric pressure. Hereby, beside a gentle surface cleaning, functional groups are formed on the fibre surfaces. Usually, the matrix material is often heated to lower its viscosity before impregnating the fibres. Therefore, it is important to know if the functional groups sustain the heat influence and still allow for a better impregnation. In this work surfaces of natural fibres were activated by a cold atmospheric pressure plasma source that offers a high treatment width and can be easily integrated into processing chains with regard to industrial applications. After activation the fibres were characterized by SEM, XPS, tensile testing and adapted wetting measurements by a Wilhelmy balance. Additionally, fibres were heated under defined atmospheres to simulate the temperature effects during the injection process. The results show an increase of oxygen containing groups and surface energy of the fibres after the plasma treatment. However, these activation effects were highly reduced after heating of the fibres. Thereby, the level of remaining activation effects depended on different plasma treatment parameters

Atmosphärendruckplasmaverfahren zur Herstellung von plasmapolymeren Beschichtungen

The invention relates to a method for depositing a plasma polymer layer in an atmospheric-pressure plasma on a metallic substrate, the plasma being obtained by a discharge between two electrodes. The invention is characterised in that at least one organic coating precursor compound is fed into the region of the relaxing plasma and is deposited on the metallic substrate as a plasma polymer layer. Nitrogen or forming gas is used as treatment gas and the at least one organic coating precursor compound is selected from the group comprising heterocyclic compounds, cyclic non-functionalized hydrocarbon and hydrocarbon with at least one functional group. The invention also relates to an article, an electrode and a capacitor which respectively comprise a metallic substrate having a surface and a plasma polymer layer on the surface. The invention further relates to a method for producing the electrode, to a method for producing the capacitor and a battery cell and a lithium-ion accumulator which comprises the electrode