Tribologically Optimized Ceramic Coatings for Cylinder Liners in Advanced Combustion Engines

Recent automotive engineering developments concerning fuel consumption regulations and decreasing material and manufacturing cost result in an increasing utilization of light metal components for automotive applications. Significant weight savings are obtained by changing the engine block material from cast iron to aluminum. Since all parts of a combustion engine interact as a system, the individual components must sustain the combustion pressure and temperature as well as wear and friction effects of moving surfaces in different environment and lubrication.

Approaches to increase combustion as well as operation efficiency and lifetime of light metal engines are ceramic and cermet coatings on the cylinder liners of die casted aluminum crankcases. Such functional and protective thermally sprayed coatings on cylinder bores include material combinations with solid lubricant ability. The used thermal spray processes are high-energetic (Atmospheric Plasma Spraying) and high-energetic hypersonic deposition methods (High Velocity Oxygen Fuel Spraying). The knowledge of the mechanical and thermophysical properties of coatings is a key requirement for an optimized stable and repeatable manufacturing process as well as for reproducible high quality composites.