Abstract Surface preparation prior to thermal spraying is a key step in ensuring a good adhesion of the coating onto the part to be coated. This article discusses the effects of laser treatment conditions on the substrate topography and coating adhesion. It investigates the properties of various types of coating applied to aluminum and titanium substrates using the PROTAL process. The paper compares the results obtained from coating of substrates directly in the "machined" state with those of a classical process (degreasing and subsequent sandblasting using aluminum oxide before coating). The results show that the PROTAL process offers the potential to avoid degreasing and steel shot blasting in numerous coating systems even with critical material combinations. In addition, the economic aspects of the process are discussed. Paper includes a German-language abstract.

Abstract Transferred-arc cleaning and roughening as discussed in the patent by Muhlberger is often used as a surface preparation method prior to low pressure plasma spray (LPPS) deposition of coatings. In this article, electrically transmitted arc cleaning is investigated as a precision cleaning method for thin films lubricating substrates as well as traditional cleaning and roughening for LPPS. A Box-Behnken reaction surface construction test is carried out with variation of the chamber pressure, the substrate distance and the torch current taking into account the transferred arc voltage, the voltage fluctuation, the current, the emitted light, and the surface cleanliness. The results of the analysis show the effect of the various independent quantities on the measured responses. Different stages in the cleaning process are determined by their sample cleanliness, their voltage level, their voltage fluctuation, their emitted light and their rate of erosion. Paper includes a German-language abstract.

Abstract This paper describes a novel application of OF-boride layers on steel surfaces. The plasma-sprayed boron carbide powder on steel was diffusion annealed to form a suitable iron-hemiboride intermediate layer with a coefficient of thermal expansion between the coefficients for the steels used and ceramic coatings to create. In the next step, this system was completed with a second plasma-sprayed layer on aluminum oxide o zirconium oxide. The adhesion of these samples was checked after dynamic loading as a result of alternating thermal loads at 600, 800, 1000 or 1200 deg C. The resulting values were compared both with the adhesion values of the same ceramic coatings on steel without a boride intermediate layer and with the adhesion values of these ceramic coatings on steel that were borated according to the classic method in a boron carbide pack with activators. Paper includes a German-language abstract.