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Crystallization of Beta NaFeO 2 from a Glass Along the Na 2 SiO 3 ‐Fe 2 O 3 Join
Author(s) -
COLLINS DAVID W.,
MULAY L. N.
Publication year - 1970
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1970.tb12013.x
Subject(s) - crystallization , isothermal process , phase diagram , superparamagnetism , mole fraction , phase (matter) , mineralogy , chemistry , mössbauer spectroscopy , analytical chemistry (journal) , materials science , crystallography , magnetic field , magnetization , thermodynamics , physics , organic chemistry , chromatography , quantum mechanics
Fine‐particle beta sodium ferrite (β‐NaFeO 2 ), rather than α‐Fe 2 O 3 , may be responsible for superparamagnetic behavior in a glass of composition (in mole fractions) 0.37Na 2 O‐0.26Fe 2 O 3 ‐0.37SiO 2 . The 700°C isothermal section of the phase diagram of the Na 2 O‐Fe 2 O 3 ‐SiO 2 system is given, showing a three‐phase field bounded by Na 2 SiO 3 ‐NaFeO 2 ‐Fe 2 O 3 ; there is no evidence for the existence (at 700°C) of compounds of molar composition 6Na 2 O‐4Fe 2 O 3 ‐5SiO 2 or 2Na 2 O‐Fe 2 O 3 ‐SiO 2 . The Moessbauer spectrum of β‐NaFeO 2 has an internal magnetic field of 487 kOe at room temperature.