Ceramic Layer Composites in Advanced Automotive Engineering and Biomedical Applications

Abstract

Light weight engineering and composite technologies are key strategies in modern product development in mechanical engineering as well as in biomedical applications, where innovation is driven by novel material concepts and surface functionalities. Designed or customized surface properties by advanced coating technologies are an important discipline in this context. Ceramic, metallurgical and cermet layers can be manufactured in a most appropriate way by high energetic thermokinetic deposition techniques like plasma spraying, electric arc and last not least by supersonic flame spraying (HVOF). These technologies perform high deposition rates, high flexibility to use various materials and their combinations and applications in micro to macro scale products. The final properties of the coatings and layer composites do not just depend on the properties of the combined materials but, as in the case of ceramic coated light metals, are distinctly affected by the occurring residual stresses and their interaction with operational load stresses. With respect to the complex geometries of most components, their dimensional and positional tolerances a further strong influence of the robot kinematics of the plasma or HVOF torches during coating manufacturing is observed. By combining the expertise in materials and manufacturing engineering coatings and composites with high performance and reliability can be achieved. This is shown in the development of functionally coated cylinder liners and crankcases for ultra light weight engines as well as for ceramic coated bioinert and biodegradable substrates in medical surgery. It will be shown that cast engine block bores can be directly coated by using an automated HVOF process, obtaining improved coating results. The internal coating process by hypersonic flame spraying is a superior technological alternative to the APS process for high quality cylinder liner and engine crankcase applications. The applications of such ceramic and cermet coatings are not limited to automotive and biomedical applications, i. e. for wear and friction properties or biomedical compatibility, but can be used for tailored thermophysical, electrophysical or catalytic properties in various technical systems.