| 摘要 |
In electrolytically producing finely divided Ni powder having a surface area in excess of 3m2/gm, electrolysis conditions include an aqueous electrolyte comprising 90 to 150 mls ammonium hydroxide per litre of solution, at least one Ni anode, at least one metallic cathode (e.g. of Ni or stainless steel which may be in mesh form), and a cathode current density of 0.007 to 0.090 amps/sq.cm. used for a period of 2 to 7 hours. After deposition the Ni powder is removed from the cathode. The ammonium hydroxide is the normal reagent grade having a concentration of 28 to 30 weight per cent of ammonia. After passing current for 2 to 3 hours, ammonium hydroxide may be added to the depleted solution, and current then be passed for a further 2 to 3 hours. The electrolyte may additionally contain NH4NO3, (NH4)2SO4 and/or nickel ammonium sulphate. The bath temperature may be from room temperature to 40 DEG C., and if the bath tends to become overheated the electrolysis may be periodically halted. The anode-cathode spacing may be 1/2 inch plus or minus 1/16 inch. After several successive depositions of Ni powder on a cathode, the cathode can be reconditioned by using it as an anode. The Ni powder can be used in fuel cell electrodes. |
