| 摘要 |
1,174,026. Porous polytetrafluoroethylenes. R. BOSCH G.m.b.H. 28 May, 1968 [30 May, 1967], No. 25541/68. Headings C3C and C3P. [Also in Division H1] Fuel cell electrodes are produced by mixing a powdered Raney alloy, powered P.T.F.E. and silver oxide or a powdered silver salt thermally decomposable to a gaseous product, shaping the mixture under pressure, sintering the P.T.F.E. by heating the shaped mixture to a temperature at least equal to the decomposition temperature of the silver compound and leading out the soluble component of the Raney alloy. The mixture may also include a powdered volatile or soluble salt which is subsequently removed by evaporation or solution to leave a porous structure. The Raney alloy may be Raney nickel or Raney palladium-silver of 20-100 Á in particle size. The silver compound may be silver oxalate or carbonate of less than 10 Á in particle size and its volume should at least equal that of the Raney alloy. The poreforming salt may be ammonium carbonate or bicarbonate which are decomposed by heating in a hydrogen atmosphere before sintering. |
