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Rapid Molten Salt Synthesis of Isotropic Negative Thermal Expansion ScF 3
Author(s) -
Hu Lei,
Chen Jun,
Fan Longlong,
Deng Jinxia,
Yu Ranbo,
Xing Xianran
Publication year - 2014
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/jace.12855
Subject(s) - crystallinity , impurity , molten salt , thermal expansion , thermal stability , chemistry , phase (matter) , inert , isotropy , materials science , chemical engineering , crystallography , inorganic chemistry , organic chemistry , composite material , physics , quantum mechanics , engineering
With a simple ReO 3 ‐type structure, ScF 3 exhibits a rare property of isotropic negative thermal expansion over a large temperature range. In this study, a rapid and low‐temperature synthesis route has been developed to prepare pure phase of ScF 3 in which Na NO 3 or KNO 3 as reaction media and Sc( NO 3 ) 3 and NH 4 HF 2 as precursors (i.e., 30 min and 310°C). The sample of ScF 3 has relatively regular morphology and shows high crystallinity as well as single‐crystalline nature. The type of molten salts has obvious impact on morphologies of the particles. Substituting Na NO 3 with KNO 3 , cubes of ScF 3 turns to be nanosticks. The thermal stability of the as‐prepared ScF 3 was investigated by thermal analysis. Molten salts play a significant role in eliminating the nonstoichiometric impurity of ScF 2.76 which is a common impurity during the conventional chemical reaction. This study reveals that molten salt is in favor of preparing those fluorides and relatives which is inert with moisture.