This paper presents the results of a study on WC-Co layers obtained by high-velocity oxyfuel spraying using different commercial systems. It explains how test samples were produced and how coating microstructure, hardness, and wear resistance was examined. The results show that the layers have excellent wear resistance and are suitable for many applications. Paper includes a German-language abstract.

This paper describes the production of self-lubricating chromium carbide-nickel coatings using the HVOF spraying process. The present work deals with the preparation of Cr 3 C 2 -Ni + CaF 2 multicomponent powders and to spray them with a minimum loss of the CaF 2 solid lubricating phase. The powders are processed by atomization with subsequent sintering and qualification processes. The microstructure of the powder and resulting layers is characterized by SEM. The content of calcium fluoride in the sprayed layer is determined using the EDS method and compared with its content in the spray powder. Wear resistance is measured using a rubber wheel tester. Paper includes a German-language abstract.

This study evaluates the through-porosity of HVOF-sprayed Hastelloy C coatings on carbon steel with respect to coating thickness and combustion pressure. The amount of through-porosity in the NiCrMo alloy layer is determined by chemical analysis, using ICP emission spectroscopy, and compared with electrochemical measurements. Paper includes a German-language abstract.

This paper compares the corrosion resistance of electrolytic hard chrome plating and HVOF-sprayed WC-Co-Cr on two steel alloys used in landing gears. Test samples were evaluated by means of salt spray testing and electrochemical measurements. Post-test metallographic examinations were conducted to investigate the failure mode of the coatings. Test results are presented along with relevant findings and observations. Paper includes a German-language abstract.

In this paper, the corrosion characteristics of two HVOF-sprayed coatings made with self-fluxing NiCrSiB powders are assessed in the as-sprayed condition. One of the coatings is also investigated after post-spray treatment with polymer sealing and after vacuum furnace fusion. It was found that cracking at lamellar boundaries dominates the corrosion behavior of the layers in the as-sprayed and sealed states, while pitting corrosion resulting from the failure of hard phases plays the main role in the melted layer. Paper includes a German-language abstract.

This paper investigates the oxidation behavior of HVAF and HVOF sprayed Cr 3 C 2 -NiCr coatings under isothermal conditions. Over the range of 700 to 900 °C, all HVAF coating-only samples showed initial rapid mass gain before levelling off in a manner indicative of the formation of a protective oxide layer. The kinetics of the process were complex and did not conform to linear, parabolic, or logarithmic rate laws. The HVOF coatings exhibited a similar response. Where variations and anomalies are observed, they are attributed to differences in microstructure, composition, and spraying equipment. Paper includes a German-language abstract.

In this paper, WC-Co reinforced polymer matrix coatings are sprayed on preheated steel and carbon-fiber reinforced substrates, producing relatively dense, adherent coatings. The particle morphology of the feedstock materials and the microstructure of the HVOF sprayed coatings are characterized and the thermal properties of the polymer powder and coatings are compared. It was found that the deposition and build-up of the polymer coating was only successful when substrates were preheated to the curing temperature of the thermosetting polyimide powder used. Layered coatings of varying polyimide and WC-Co content have been successfully deposited, showing that it is possible to produce graded composite coatings consisting of pure polymer at the substrate and pure WC-Co on the surface. Paper includes a German-language abstract.