CORROSION SIMULATION TESTS OF PHOSPHORIC-ACID FUEL-CELLS

Carbon corrosion in a phosphoric acid fuel cell was experimentally simulated by causing hydrogen starvation or by intentionally introducing defects (e.g., local removal of specific components) into the cell. In some cases, significant carbon corrosion was observed at the fuel outlet area of the cathode. Pressurization accelerates the carbon corrosion rate. Carbon corrosion at the cathode was also observed just above or along the fuel flow channel downstream of a matrix defect. Defects in the matrix layer were critical to the corrosion problem. Defects in the anode also gave a substantial effect, but defects in a cathode were allowable. There was no significant difference in the corrosion resistance of a cathode in contact with a wet proofed substrate and an electrolyte reservoir substrate. Series fuel gas flow was effective in giving increased corrosion resistance compared with parallel gas flow.