Carbon/Carbon Composites—Solid Rocket Nozzle Material Processing, Design, and Testing

One hundred and one ring shapes (2 to 16 in. in diameter) of carbon/carbon composites have been tested and evaluated to determine the processing cycle, the design properties, the ablative performance in a solid rocket nozzle environment, and the reinforcement tailoring for design applications. A carbon/carbon composite with a carbon or graphite reinforcement (cloth, fiber, felt, yarn, or granular) and a carbon or graphite bonding matrix (pitch, resin, or pyrolytic graphite) has demonstrated a capability to replace a warm standard nozzle ablative (carbon or graphite cloth phenolic) and room temperature structural (steel or aluminum) shells with a single hot material nozzle design. The carbon/carbon material provides an improved nozzle and missile performance through a lower nozzle weight volume and simpler design. The carbon/carbon material uses a 5500 F maximum processing cycle and develops a room temperature ultimate strength and modulus ranging from 3 to 88 ksi and 1.2 to 17.0 × 106 psi, respectively, an ablation erosion rate of 0 to 10 mil/s, and a reinforcement orientation of 0 to 90 deg with respect to the nozzle center line. In addition, the material offers good mechanical properties, dimensional stability, and structural integrity for a nozzle operating temperature of 5500 F and a pressure of 500 psi. The carbon/carbon limitations are longer procurement time, a need for additional processing and material properties, a high cost per pound in development quantities, and a greater design application analysis time than with existing standard ablative and structural materials.