Novel Manufacture Technology for a Cylinder Liner by Using Thermal Spraying for the Application in a Plastic Cylinder Block

For weight reduction, a concept was generated that replaces the conventional material of cylinder blocks such as cast iron with plastic materials. The challenge is to produce a cylinder liner that combines a wear and corrosion protective coating with a cooling water channel and a thermal barrier coating that is mounted in the plastic cylinder block and bears the dynamic forces and heat generated by the combustion of the fuel.

Because of the great difficulty to generate an inside coating with the HVOF technique in a small borehole, an outside coating on a core was utilized instead. The core was removed with electromechanical and chemical methods after the thermal spraying process. In order to achieve a high corrosion resistance during the chemical elimination process, three different, typical wear protective materials (WC-Co standard, WC-Co with fine carbide, and WC-FeCrAl) were utilized and compared in corrosion tests. Moreover, a copper layer with a cooling water channel and the YSZ thermal barrier layer were deposited by means of cold spray and atmospheric plasma spray, respectively. In the end, a combustion test was performed to prove the heat resistance of the plastic cylinder block prototype with the cylinder liner.