This paper provides results from experimental studies with regard to novel, thermally sprayed coatings for tribological applications, which consist of mechanical mixtures of cast iron powders (2.16% by weight C and 5.18% by weight Si) and solid lubricant (calcium fluoride or iron oxide) produced in an amount of 10 to 20% by volume. It was established that a basic phase of initial cast iron powder and detonation coatings is gamma-Fe and it is alpha-Fe in plasma coatings. Oxide inclusions which are products of cast iron oxidation are observed in coatings structure. Metallographic investigations showed an uniform distribution of solid lubricant inclusions in a metallic-matrix of coatings. Tribotechnical tests of coatings containing 20 vol. % calcium fluoride carried out in conditions of room temperature indicated that the best antifriction properties were obtained for coatings with calcium fluoride additions which were sprayed by supersonic air-gas plasma method. Paper includes a German-language abstract.

The processing of metallic alloys with the atmospheric HVOF process requires a uniform setting of the particle parameters, particle temperature and velocity, as these determine the tendency towards oxidation and the flattening behavior of the particles. Using the example of a NiCr alloy, this paper examines the effects of different particle diameters of a typical HVOF grain fraction on the achievable uniformity of processing. In addition, particle parameters are correlated with the process variables fuel gas composition and spray distance as well as the resulting application efficiency in order to determine whether they can be influenced. The particle properties of surface temperature and speed are characterized with the aid of a high-speed particle pyrometer. It is shown how, with the help of this particle diagnosis, an on-line process control can be used as proof of quality assurance. Paper includes a German-language abstract.

Thermally sprayed coatings made of polyetheretherketone (PEEK) and polyphenylene sulfide (PPS) are becoming increasingly interesting, especially for corrosion protection applications at elevated temperatures in the chemical industry. In contrast to conventional polymers these materials melt at much higher temperatures. Furthermore, PPS and PEEK show enhanced mechanical and chemical stability. Instead of HVOF and plasma spraying, in this paper much simpler and low-cost flame spraying is used because of these advantages. The polymers are investigated along the entire deposition process in order to exclude possible decomposition. Attempts are made with various adhesive layers to reduce the unacceptably high preheat temperatures. The corrosion protection features are examined by means of corrosion tests with various media. The results of the experiments presented in this paper promise coatings of high performance thermoplasts a great future as anticorrosive coatings. Paper includes a German-language abstract.