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High-temperature Enthalpies and Entropies of Chalcopyrite and Bornite.
NTIS: PB 196 683 :10 pages
Enthalpies were determined for synthetic chalcopyrite (cufes2) between 298 deg. and 1,050 deg. K and for synthetic bornite (cu5fes4) between 298 deg. and 1,100 deg. K by copper-block drop calorimetry. Two transitions were found for each compound. The lower transitions were both crystal transformations from tetragonal (low-temperature form) to cubic (high-temperature form). The chalcopyrite transformation occurred at 830 deg. K with a heat of transformation of 2,405 cal/mole; the bornite transformation was at 485 deg. K with a heat of 1,430 cal/mole. The other transitions were of the second order and were presumed to be magnetic in character. The second-order transitions for chalcopyrite occurred at 930 deg. K, and the one for bornite at 540 deg. K.
IH; Report of Investigation;
NTIS Accession No.
NTIS: PB 196 683
Page last reviewed: September 2, 2020
Content source: National Institute for Occupational Safety and Health Education and Information Division