Importance

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Abstract

This disclosure is directed to a gas diffusion electrode, e.g., an oxygen (air) electrode, having a conductive, porous, sintered, plaque metal substrate containing generally spherically-shaped anchor site depressions on its active layer-contacting surface; an active layer containing catalyzed or uncatalyzed carbon particles and whose plaque-contacting surface includes anchor portions which interlock with the anchor site depressions and assist in securing the active layer to the plaque substrate, and a hydrophobic backing (wetproofing) layer in contact with the other surface of the active layer. The plaque is made by forming, e.g., by rolling or pressing, the metal powder, preferably silver, containing particulate extractable material on one face or surface thereof into a thin plaque; sintering the plaque containing the extractable material at temperatures of from about 1000.degree. to about 1300.degree. F. for time periods of from about 2 to about 30 minutes and thereafter removing the extractable material to produce a plaque electrode substrate having anchor site depressions in one surface. The active layer material is then deposited, preferably by filtration, on the plaque surface having such depressions followed by depositing the hydrophobic layer, also preferably by filtration.

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First Claim