| 摘要 |
The invention provides platinum or platinum alloy powders for use in fu el cells and for chemical reactions. The powders are characterized by a high surface area and, at the same time, low chlorine contents. The powders are prepared by forming a melt which contains, as starting substances, a low melting mixture of alkali metal nitrates, a chlorine-free platinum compound and optionally chlorine-free compounds of alloying elements, the melt is then heated to a reaction temperature at which the platinum compound and the compounds of alloying elements thermally decompose to give oxides, the melt is then cooled and dissolved in water and the oxides o r mixed oxides formed are converted into platinum or platinum alloy, powders by .subsequent reduction. Binary or ternary eutectic mixtures from the LiNO, - KNO3 - NaNO3 system are suitable as a low melting mixture of nitrates of the alkali metal s. Hexahydroxoplatinic-(IV)-acid is preferably used as a chlorine-free platin um compound. |
