Metal‐Carbon Composite Materials from Fiber Precursors: I . Preparation of Stainless Steel—Carbon Composite Electrodes

A novel approach to fabrication of composite metal--carbon electrodes has been developed. Stainless steel 316L fibers (2 mu m diameter) and C fiber bundles (20 mu m diameter) were combined with cellulose (as the binding agent) into an interwoven paper preform. The composite paper preform was then sintered to a stainless foil substrate to form the electrode structure. "Optimal sintering", experimentally determined by the percentage of initial C remaining in the sintered electrode, was achieved at 1423K in H sub 2 for 2.5 min. Gas flow of H sub 2 was maintained at 10 cm exp 3 /min (STP) or a linear velocity of 2.6 cm/min with a total pressure of 101 kPa. These conditions were consistent with the thermodynamics and kinetics of sintering and catalyzed C gasification. The composite electrode structure was shown to possess the high surface area characteristic of carbon black and the structural integrity of sintered metals. The degree of intermixing of fibers in the composite paper preforms and in the sintered electrodes was clearly shown by scanning electron microscopy (SEM). Volumetric BET measurements showed a surface area of approx 760 m exp 2 /g of C for the sintered composite electrode structure compared to approx 790 m exp 2 /g for the precursor C fiber. It is believed these preparation techniques offer flexibility in the properties of the composite electrode (i.e. specific surface area, void volume, thermal and electrical conductivity, etc.). Photomicrographs. 34 ref.--AA