| 摘要 |
A process for producing sintered fuel cell electrodes comprises forming at least two layers of uncompacted metal powders e.g. Ni, Co, Au, Ag, Pt group metal or alloys in a die, one layer forming a coarse pore layer and the other a fine pore layer and at least one layer containing an expanding agent, compacting the layers together and then sintering. The metal powder has a particle size of 1 to 10 microns, the expanding agent in the fine pore layer has a particle size of less than 40 microns and a particle size of 100 to 150 microns in the coarse layer. The expanding agent may be ammonium bicarbonate or a compound which thermally decomposes to form an oxide of B, Al or Li e.g. a carbonate or oxalate of Al or Li. The sintered electrodes may be heated to 600 DEG -1000 DEG C., impregnated with a Li, B or Al compound and then heat treated at 400 DEG -1000 DEG C in an oxidizing atmosphere to form the oxide of Li B or Al. Oxidation catalysts such as nickel oxide, Ag or Pt may also be formed in the sintered electrode by impregnating with a decomposable metal salt such as chloroplatinic acid and nickel nitrate. The sintered electrodes may also be coated with Ni or Pt by chemical or electrolytic means. In an alternative embodiment the coarse and fine powder layers may be separated by a layer of expanding agent such as ammonium bicarbonate. Double planar electrodes may also be made by forming the following layers in a die; 1) Fine pore powder layer 2) Coarse pore powder layer 3) A series of metal compacts placed on layer (2) 4) Spaces between the compacts filled with expanding agent 5) Coarse pore powder layer 6) Fine pore powder layer The assembly of layers is then compacted and sintered. |
