SMuK 2021 – scientific programme

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P: Fachverband Plasmaphysik

P 17: Poster II

P 17.7: Poster

Friday, September 3, 2021, 14:00–16:00, P

Influence of the surface roughness on the adhesion of thermal plasma spray Al2O3 coatings — •Tony Krüger¹, Thorben Kewitz¹, Holger Testrich¹, Rüdiger Foest¹, and Franz Faupel² — ¹Leibniz Institute for Plasma Science and Technology, 17489 Greifswald, DE — ²Kiel University, 24143 Kiel, DE

In industrial plasma spray processes, masks are used to protect areas of the work piece from unwanted coating. However, gradual accumulation of material on masks can lead to changes in the flow dynamics near masks causing loss of contour accuracy and coating quality. Hence, generating surfaces conditions for masks that affect film adhesion and promote swift delamination becomes attractive. In thermal spray processes, bonding between the coating and a substrate surface is mainly established by mechanical anchoring, next to physical and chemical interactions. Here, the influence of the surface roughness on the coating adhesion is studied systematically. The surface roughness of steel was varied by means of plasma electrolytic polishing in order to provide a series of samples with a defined range from 2.5µ m ≥Ra≥0.02µ m, measured using surface profilometry and white light interferometry, for critical method comparison. Moreover, the effect of additional interface layers (TiN, SiOx) on the film adhesion was investigated. Samples were spray coated with Al2O3 (2kg/h) using a Oerlicon Metco F4MB-XL Spray Gun (DC, I=600A, gases: Ar (41 NLPM), H2 (14NLPM)). The relation between thin film adhesion and surface conditions (roughness and presence of interface layers) is examined (Funded by the EU and the State of Mecklenburg-Western Pomerania (TBIV-1-321)).