Ceramic Matric Composites C/ SiC and SiC/ SiCCopyright: Fraunhofer ILT
Ceramic Matrix Composites were developed to combine the positive properties of ceramics, like high strength as well as thermal and chemical stability, with a reduced brittleness. Ceramic fibres are embedded within a ceramic matrix, although with reduced adhesion. The resulting freedom of movement enables energy dissipation during deformation and cracks in the matrix are not transferred to the fibres. Originally developed for reentry bodies of spacecrafts they are now applied for bearings as well, among other applications.
The CMCs C/ SiC and SiC/ SiC are, among other materials of this group, envisioned as future materials for gas turbines. Cooling channels with high angles towards the surface normal are necessary for that. Furthermore the requirements concerning precision and productivity are very high. Laser Drilling is therefore a solution to create such drill holes. The challenges that need to be faced are possible fibre burning and oxidation.