Brake Pedal to the Metal - Development of Environmentally Safe Coatings

Brake pedal to the metal – Development of environmentally safe coatings

Fine dust from tribological contact occurs in a wide variety of applications. A new methodology of tribological and toxicological tests is presented to determine the environmental impact of fine dust from brake discs coated by thermal spraying in the future. In this study, the entire coating process from powder feedstock to coating deposition is analyzed in order to track the formation of harmful chemical substances. WC-CoCr is chosen as an exemplary alloy for this study as it has been one of the first proposals for brake disc coating. The powder is examined by ICP-analysis. In addition, Cr(VI)-levels are determined by HPLC. Central in the emission analysis is the exposition of A549 in an air‑liquid‑interface. In this way, artificial respiration and homogenous exposition is guaranteed. Furthermore, metabolic activity is determined by CCK8-assays. Two different findings relevant for thermal spraying are being reported. A) Analyzing Cr (VI)-levels, it is concluded that the powder feedstock is Cr (VI)-free and neither formed during the thermal spraying process. B) The demonstrated method to determine cell activity is suitable for further emission studies in the context of brake systems.

Keywords: Wear, Brake Disc, HVOF, emission