Effect of Graphitization on Solid State Bonding of Carbon to Nickel*

Five carbons with different graphitization degrees, which were heat-treated at temperatures of 1273 to 3273K, were prepared. These carbons were bonded to nickel in a vacuum, using an RF-induction furnace, with joining temperatures of 1073 to 1273K. On the basis of the results of these experiments, the effects of the graphitization degree on the solid-state bonding of carbon to nickel were examined. Carbon heattreated at 1273K remains amorphous, whereas most of the carbons heat-treated at 3273K change into graphite because the graphitization degree increases with increasing heat treatment temperature. Strong bonding of amorphous carbon to nickel is not accomplished. The bending strength or joinability of carbon (with a graphitization degree lower than 0.28)/nickel joints depends on the joining temperature. Good bonding of carbon with a graphitization degree higher than 0.28 to nickel is achieved regardless of the joining temperature. The graphitization degree and thermal stress affect the joinability and bending strength of the joints.