In this work a cold atmospheric pressure plasma jet was mounted above a distilled water reservoir to study the influence of a water surface on reactive oxygen and nitrogen species (RONS) generation. The RONS, namely O ₃ and NO ₂ , were measured by multi-pass cell Fourier transform infrared absorption spectroscopy in the far-field of the jet. A shielding gas device was used to control the ambient environment of the effluent. The liquid surface has nearly no influence on the RONS dynamics as a function of shielding gas composition. It was found, however, that the interaction with the liquid surface increases the density of NO _x by a factor of 2–3 due to local increase in H ₂ O concentration through evaporation of water from the liquid surface. In contrast to the case of ambient humidity increase, this locally higher H ₂ O density distinctly influences the ratio of water to oxygen and nitrogen which results in a higher generation of OH molecules.

In this work, the results of SiO _x thin film deposition by an atmospheric pressure plasma jet using HMDSO (hexamethyldisiloxane) as precursor are presented. The experiments were performed for different process parameters like initial applied power, substrate to nozzle distance and speed of the moving substrate holder. In order to determine the properties of deposited films the samples were analyzed by scanning electron microscopy, transmission electron microscopy, atomic force microscopy and profilometer. The formation mechanism of particles and their size distribution depending on the process parameters are described and discussed. The results show the possibility to change properties of deposited films and particle formation by tuning the experimental settings.

Electrical and thermal measurements were conducted during the plasma electrolytic polishing (PEP) of cemented tungsten carbide (WC-Co) materials to characterize energetic aspects of the process in relation to the temporal development of the gaseous layer near the workpiece. The power transferred to the workpiece is determined using a calorimetric probe and employing the time derivative of the temperature curve. It shows distinct heating phases due to the generation of the gaseous layer. At the beginning of the process, a typical power of 367 ± 17 W is transferred to the workpiece of a surface area of 14 cm2. At longer process times, a stabilized gaseous layer limits the power transferred to the workpiece to 183 ± 3 W. In an attempt to describe the heat transferred to the electrolyte, the electrolyte temperature was measured using a thermocouple situated 15 mm away from the workpiece. The local electrolyte temperature increases from 70 to 81 °C for an immersion depth of 20 mm. Moreover, the spatiotemporal development of the electrolyte temperature was obtained by 2D-hydrodynamic modeling using COMSOL Multiphysics®. The modeling results for the local temporal temperature development are in excellent agreement with the experimental values when the turbulent model is applied up to t = 65 s. Afterward, the laminar model leads to a better agreement. Furthermore, line scan x-ray photoelectron spectroscopy revealed that aliphatic carbon was preferentially removed. Only a slight compositional gradient in the vertical direction after the PEP process was observed.

Energy flux measurements by a passive thermal probe were performed for a diffuse coplanar surface barrier discharge to determine the transfered energy to a substrate in dependence on the substrate distance to the electrode and working gas of the discharge. The largest energy flux was found at ∼300–400 m above the electrode surface to be about 900 mW cm ⁻² . Furthermore, an active substrate cooling mechanism could be identified within the plasma caused by gas convection flows for very small distances. Variation of the working gas (argon, molecular gas) indicates the importance of the gas and surface reactivity for the transferred energy to the substrate. Molecular gases result in a remarkably higher energy flux compared to rare gas.