کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
9781714 | 1511635 | 2005 | 10 صفحه PDF | دانلود رایگان |
عنوان انگلیسی مقاله ISI
Immiscibility in the NiFe2O4-NiCr2O4 spinel binary
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کلمات کلیدی
موضوعات مرتبط
مهندسی و علوم پایه
مهندسی مواد
مواد الکترونیکی، نوری و مغناطیسی
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چکیده انگلیسی
The solid solution behavior of the Ni(Fe1ânCrn)2O4 spinel binary is investigated in the temperature range 400-1200 °C. Non-ideal solution behavior, as exhibited by non-linear changes in lattice parameter with changes in n, is observed in a series of single-phase solids air-cooled from 1200 °C. Air-annealing for 1 year at 600 °C resulted in partial phase separation in a spinel binary having n=0.5. Spinel crystals grown from NiO, Fe2O3 and Cr2O3 reactants, mixed to give NiCrFeO4, by Ostwald ripening in a molten salt solvent, exhibited single-phase stability down to about 750 °C (the estimated consolute solution temperature, Tcs). A solvus exists below Tcs. The solvus becomes increasingly asymmetric at lower temperatures and extrapolates to n values of 0.2 and 0.7 at 300 °C. The extrapolated solvus is shown to be consistent with that predicted using a primitive regular solution model in which free energies of mixing are determined entirely from changes in configurational entropy at room temperature.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Journal of Physics and Chemistry of Solids - Volume 66, Issue 6, June 2005, Pages 1112-1121
Journal: Journal of Physics and Chemistry of Solids - Volume 66, Issue 6, June 2005, Pages 1112-1121
نویسندگان
S.E. Ziemniak, A.R. Gaddipati, P.C. Sander,