1384. HEDVALL, J. A., AND GUSTAVSON, E. [Catalytic Activity and Ferromagnetism. I.] Svensk Kem. Tid., vol. 46, 1934, pp. 64-65; Chem. Abs., vol. 28, 1934, p. 4971.

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Literature Abstracts

It has been shown recently that the reactivity of solids is increased by phase transformations that do not affect the lattice structure. Hence, it is important to investigate whether the disappearance of ferromagnetism produces a similar change. For this purpose, experiments were made on the reaction N₂O=N₂+O, with pure Ni as the catalyst, at 330°-380°, since no alteration in the Ni lattice has been observed in a temperature interval of 1,000°. Between 330° and 359° the decomposition was constant, but at approximately 359° there was an abrupt rise in the decomposition-temperature curve. The Curie temperature for this specimen of Ni was 358°-360°. Control experiments with N₂ or O₂ instead of N₂O gave curves without this sharp break, as did experiments with N₂O over NiO. Experiments with other samples of Ni with different Curie points showed the same agreement between the temperature at which the break occurs and the Curie temperature. The sudden application of a magnetic field, either above or below the Curie point, produced no appreciable effect on the decomposition.