Key Laboratory of Materials Physics of Ministry of Education of China, School of Physical Science and Engineering, Zhengzhou University
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DOI:
10.7502/j.issn.1674-3962.2015.07.03
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Abstract:
if we prepare new negative thermal expansion material properties which have Good performance ,they will have great value. A novel negative thermal expansion (NTE) material Sm0.85Sr0.15MnO3-δ was synthesized by solid-state method. It is originated in SmMnO3 with Sr2+ partly substituting Sm3+. Ceramic Sm0.85Sr0.15MnO3-δ exhibits NTE coefficient of -10.08×10-6/K from 360 to 873 K, which crystallized in orthorhombic structure (space group pbnm) with regular morphology and uniform grain size. The relative density measured by Archimedes drainage method is 95.5%. The results of X-ray diffraction and TGA-DSC suggest the negative phenomenon relates to the electron transfer of Mn ions. Mn4+ dramatically converted into Mn3+ accompanied by Mn4+O6 octahedral distortions and oxygen defects as temperature increasing. It is found that the sample volume continually decreases.