Compatibility studies between pyrolytic carbon and nickel

Abstract

It is well known that carbon is graphitized by foreign substances. In previous work, graphitization of carbon fibre by nickel was found at temperatures as low as 700° C, but it was difficult to establish the graphitization rate because of the fibre's round cross-section and the variable orientation of the crystallites. In this work, pyrolytic carbon was used instead of the carbon fibre because of its flat surfaces and the preferred orientation of the carbon networks. The pyrolytic carbon which was electro-deposited with nickel, was held at high temperatures. A nickel layer was observed in the pyrolytic carbon, and the carbon area through which the nickel layer passed became graphitized. The graphitization rates were constant at each temperature. And activation energy of 39.7 kcal mol⁻¹ was obtained from the graphitization rates, which agrees well with the activation energy for diffusion of carbon atoms in nickel. No obvious difference of the graphitization rates was recognized between the directions parallel and normal to the carbon networks.