In this paper, induction plasma spray processing is used to produce free-standing-parts of molybdenum silicide-B composition, the boron, and molybdenum silicide powders being blended to form the initial spray powders. The oxidation resistance for each of these composites is compared to those of molybdenum silicide and molybdenum disilicide plasma spray deposits, produced under identical conditions. The results indicated that the 2.0 wt% boron sample had excellent oxidation resistance and showed a mass change of almost zero after 24 hours of high temperature oxidation (1210 deg C). Paper includes a German-language abstract.

This paper reports on the synthesis of SiC material through the decomposition of silanes in a thermal high frequency (HF) plasma. The process is based on thermal plasma technology for chemical deposition from the gas phase and on suspension plasma spray technology, in which a liquid or suspension is injected axially and atomized in the plasma flame. The liquid silane then decomposes, and forms SiC with some gaseous by-products such as HCl. Various plasma parameters were varied, for example the plasma power level, the plasma gas composition, the chamber pressure, and the silane composition. The paper also presents first investigations into the elementary and phase composition as well as the morphology of the powders and coatings. Paper includes a German-language abstract.

This paper deals with the production of porous functional coatings by means of high-frequency plasma spraying. This technology is presented for the first time in connection with controlled, open, porous, and graded structures. Materials such as pure metals (molybdenum and titanium), high-temperature alloys (Inconel), and ceramics (yttrium oxide-stabilized zirconium oxide) have been processed with several powder fractions with extremely different process parameters (container pressure, power, plasma gas composition). The samples were tested for their characteristic properties (porosity, effective pore sizes and permeability). The status of development is reported and potential attractive industrial applications are mentioned. Paper includes a German-language abstract.

More than 20 years the Institute of Technical Thermodynamics of the German Aerospace Center (DLR) in Stuttgart has been active in the field of plasma spray technology with improvements of spray equipment and their application. At the beginning the DC vacuum plasma spray method was in the center of interest and knowledge gained from rocket technology helped to develop supersonic nozzles for the plasma spray torches producing plasma jets with increased velocity and improved laminarity in order to get denser coatings with higher quality. In the meantime also nozzles for subsonic conditions with controlled expansion of the plasma jet leading to considerably increased deposition efficiency were developed as compatible parts for already existing equipment and made available on the market. In the next step also the DC plasma torches themselves have been improved. Recently a modern equipment for RF plasma technology could be developed and installed, where some new ideas could be realised. Paper text in German.