| 摘要 |
An electrode for a fuel cell is produced by subjecting an alloy to heat treatment sufficient to render it sensitive to intercrystalline attack and then etching it with acid at a temperature between 60 DEG C. and the boiling point of the acid so as to render the alloy porous; the etching is stopped before total disintegration of the alloy occurs. The alloy is preferably austentic stainless steel which is heat treated at 400-800 DEG C. The following etching media are referred to: (a) a solution of copper sulphate and sulphuric acid, (b) a solution of nitric acid and hydrofluoric acid, (c) a solution of sulphuric acid containing a soluble ferric salt, (d) a solution of hydrochloric acid containing a soluble chloride (e) a solution of an organic acid e.g. lactic or maleic acid. After etching the electrodes may be treated with an aqueous ammonia solution or with a mixture of nitric acid and hydrofluoric acid. |
