The paper describes a practical method for real-time measurement of active power in a dielectric barrier discharge by calculating a Lissajous figures based on the Manley formula. Such a method is very useful for controlling the output ozone concentration in ozone generators taking into account the active power in a DBD reactor. A dielectric barrier discharge (DBD) in atmospheric pressure air was excited by a high-voltage pulse power supply. The active power of the reactor was estimated from the area of the Lissajous figure formed by the V-Q traces, which is directly proportional to the energy consumed per cycle at voltages of 8 and 12 kV, respectively.

Influence of plasma-based ion implantation and deposition on the structure, internal stress and mechanical properties of nanocrystalline ZrN coatings

Nanostructured ZrO 2 ceramic PVD coatings on Nd-Fe-B permanent magnets

Influence of powerful plasma impacts on several materials used for the construction of energy systems, i.e. different grades of steels as well as tungsten coatings, has been discussed. Irradiations of these materials with hydrogen and helium plasma streams have been performed in several high-current-pulse and quasi-stationary plasma accelerators which provided the variation of a power load upon the exposed surface as well as changes of the particle flux in wide ranges: the energy flux density in the range of 1-25 MJ/m(2), particle flux up to 10(26)-10(29) ion/m(2)s,the plasma stream velocity - up to about 500 km/s, and the pulse duration in the range of 1-250 mu s. A response of the investigated materials to extreme plasma loads, which are relevant to transient events in fusion reactors, is briefly discussed. It is demonstrated that a broad combination of mechanisms of powerful plasma interactions with various materials includes not only a surface damage caused by different erosion mechanisms, but under certain conditions it may also result in a significant improvement of material properties in the near surface surface layer of several tens-mu m in thickness. Some improvement of the structure and substructure of such a layer may be caused by the high-speed quenching, the shock wave formation and material alloying with plasma- and coating-species. The creation of unique surface structures and a considerable improvement of physical and mechanical properties of different materials can be achieved by the pulsed plasma alloying, i.e. pre-deposited coating modifications and mixing caused by the impacting plasma streams.

Structure and properties of nanostructured ZrN coatings obtained by vacuum-arc evaporation using RF discharge

The results of the development of the high-frequency method in combination with a vacuum arc one for surface coating and surface modifications with pulsed plasma streams are presented. The combined method was applied for deposition of multi-layer coatings with a reduction of droplet formation and decrease of the substrate temperature. It provided metal and dielectric coatings under the substrate temperature ⩽ 200°C. The (TiN–Ti) coatings were deposited onto organic materials and metals. Amorphous and hypocrystalline dielectric films of Al2O3 were obtained. Also, the material surface properties were improved by surface treatment with pulsed plasma streams. This treatment led to melting of the surface layer, introduction of nitrogen into the liquid surface layer and subsequent fast solidification. The formation of modified fine-grained surface layers of 30μm in depth was observed as a result of a plasma processing. An essential improvement of wear properties of treated samples was obtained. Pulsed plasma processing of FeB or TiAlN coatings has shown that under the plasma treatment intensive mixing of the materials of coating with the material of substrate was achieved.