Heat durability of carbon fiber reinforced nickel composites

Carbon fi ber is a highly heat resistive material in an oxygen free atmosphere. Nickel is also a heat resistive metal and an important element for a superalloy. We can expect an excellent heat durable composite when they are combined. Nickel was electroplated on a carbon yarn to form a monofi lament composite. When the high strength fi ber was tested, the composite started to lose its strength at 600 C. The deterioration was caused by graphitization of the carbon in the fi ber. This is caused by the difference of the graphitization degree between crystallites in a fi ber. A high modulus carbon fi ber has little difference of the graphitization degree in a fi ber. The high modulus fi ber did not react when tested and the fi ber strength was maintained after heat treatment at 1100 C for 9 h. From the results, the high modulus carbon fi ber composite is promising to be durable at a high temperature.