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Title: Solid state synthesis of BiFeO 3 occurs through the intermediate Bi 25 FeO 39 compound
Abstract The solid‐state synthesis of perovskite BiFeO3has been a topic of interest for decades. Many studies have reported challenges in the synthesis of BiFeO3from starting oxides of Bi2O3and Fe2O3, mainly associated with the development of persistent secondary phases such as Bi25FeO39(sillenite) and Bi2Fe4O9(mullite). These secondary phases are thought to be a consequence of unreacted Fe‐rich and Bi‐rich regions, that is, incomplete interdiffusion. In the present work, in situ high‐temperature X‐ray diffraction is used to demonstrate that Bi2O3first reacts with Fe2O3to form sillenite Bi25FeO39, which then reacts with the remaining Fe2O3to form BiFeO3. Therefore, the synthesis of perovskite BiFeO3is shown to occur via a two‐step reaction sequence with Bi25FeO39as an intermediate compound. Because Bi25FeO39and the γ‐Bi2O3phase are isostructural, it is difficult to discriminate them solely from X‐ray diffraction. Evidence is presented for the existence of the intermediate sillenite Bi25FeO39using quenching experiments, comparisons between Bi2O3behavior by itself and in the presence of Fe2O3, and crystal structure examination. With this new information, a proposed reaction pathway from the starting oxides to the product is presented.  more » « less
Award ID(s):
1841466
PAR ID:
10489649
Author(s) / Creator(s):
; ; ; ; ;
Publisher / Repository:
JACE
Date Published:
Journal Name:
Journal of the American Ceramic Society
ISSN:
0002-7820
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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