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Spectral determination of the curie point
Spcctrochimica
Acts,
1053,
Vol. 0, p. ‘75.
Communication
Perwrvm
Press Ltd.,
London
to the Third International Spectroscopy
CoUoquiu;n, High Leigh, 1952
Spectral determination of the Curie point J. 11.
LOPEZ
Instibto
DE
Azcosa
and J. ?/I. LOSADA
Geologico y Miner0 de Espana,
Madrid
A series of experiments to determine the Curie point in nickel by measurements of the absolute intensity of the spectra has been made. To begin with, nickel. pure except for 0.05% of cobalt was taken, and t,he spark spectra recorded with a Hilger large dispersion spectrograph. The Feussner type controlled spark was found better than other circuits. The spark spectra were studied while the samples were contained in a specially constructed furnace, which has been described to the 13th Congress of the G.A.M.S., varying the t,emperature in steps of 10°C with a temperature control accurate to 2OC. The densities of various spectral lines were plotted against temperatures, and they all were found to give similar curves, for example, a typical line in the range of 250’ to 41O’C was shown. This revealed a density maximum at 300” and a minimum at 360” which suggest fist a change in the nickel and then a magnetic transformation which occurs at 353’C. At the latter temperature there are anomalies in the coefficients of expansion and specific heat curves of nickel. Other spark circuits and other wavelengths are being studied to learn more about this type of change.
25
Acts,
1053,
Vol. 0, p. ‘75.
Communication
Perwrvm
Press Ltd.,
London
to the Third International Spectroscopy
CoUoquiu;n, High Leigh, 1952
Spectral determination of the Curie point J. 11.
LOPEZ
Instibto
DE
Azcosa
and J. ?/I. LOSADA
Geologico y Miner0 de Espana,
Madrid
A series of experiments to determine the Curie point in nickel by measurements of the absolute intensity of the spectra has been made. To begin with, nickel. pure except for 0.05% of cobalt was taken, and t,he spark spectra recorded with a Hilger large dispersion spectrograph. The Feussner type controlled spark was found better than other circuits. The spark spectra were studied while the samples were contained in a specially constructed furnace, which has been described to the 13th Congress of the G.A.M.S., varying the t,emperature in steps of 10°C with a temperature control accurate to 2OC. The densities of various spectral lines were plotted against temperatures, and they all were found to give similar curves, for example, a typical line in the range of 250’ to 41O’C was shown. This revealed a density maximum at 300” and a minimum at 360” which suggest fist a change in the nickel and then a magnetic transformation which occurs at 353’C. At the latter temperature there are anomalies in the coefficients of expansion and specific heat curves of nickel. Other spark circuits and other wavelengths are being studied to learn more about this type of change.
25