Development of a new cost-effective ceramic composite for re-entry heat shield applications

Within the Manned Space Transportation Programme ESA have launched study projects to assess an advanced heat shield concept for re-entry capsules relying on a C/SiC ceramic matrix composite for the hot structure. MAN Technologie has developed a C/SiC composite with a polymer derived SiC matrix and carbon fibre woven fabrics as reinforcement which is being tested in this technology study. It is manufactured by a liquid polymer impregnation (LPI) process. Repeated impregnation and pyrolysis cycles are employed to reach the proper density of 1.75 g/cm 3. The main mechanical properties of the fabric reinforced LPI-C/SiC, determined with test pieces taken from complex parts, are a tensile strength of 270 MPa along with a strain to failure of 1.2%, a compressive strength of 440 MPa, and an interlaminar shear strength of 30 MPa. A strength retention of 80% was found after 30 min exposure to air at 1870K and in LCF tests with a peak stress of 200 MPa a million cycles were achieved without rupture. Integrally laminated panel segments have successfully been tested up to 1800 K in air of 20 hPa with high temperature gradients (>1000 K) and transients (30 K/sec) without damage. these results demonstrate that the LPI-C/SiC with fabric reinforcement provides a proper performance and reliability to open up the option for a CMC heat shield application in advanced crew transfer vehicles.