Study to Assess the Suitability of C/C-SiC as Material for Piston Rings

Abstract

The potential of ceramic matrix composites in a diversity of applications is being researched. High load brake disks have proven to be a successful adaptation of the materials properties for an automotive system. The paper summarizes the first steps towards the possibility of piston rings made from a ceramic matrix composite. After a brief description of the selected ceramic matrix composite the basic requirements for piston rings during assembly and operation as well as possibilities to assess the suitability are discussed. To achieve an overview of how the fibre orientation influences the material properties a selection of carbon fibre preforms are selected and processed into ceramic matrix composite piston rings before being tested. The results prove that one part C/C-SiC piston rings are possible as the basic strain during instalment on pistons is the first challenge to be assessed. Furthermore an insight towards the dependencies between fibre orientation and properties of the filigree piston rings is given. While the planed friction results are not available the manufacturing experience is discussed next to the strain test to form an initial assessment of the suitability. The results prove that C/C-SiC has potential as piston ring material and the tensile strength for assembly is demonstrated. Further research regarding the optimization of the preform or other manufacturing steps could prove to generate properties tailored to piston ring requirements.