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Title: Structural evolution, sintering behavior and microwave dielectric properties of (1−x)Li{sub 2}TiO{sub 3} + xLiF ceramics

Graphical abstract: - Highlights: • Structure, sinterability and dielectric properties of LiF-doped Li{sub 2}TiO{sub 3} were studied. • Li{sub 2}TiO{sub 3} can be densitied (TD 98%) at lower sintering temperature by LiF additions. • Excellent microwave dielectric properties could be obtained. - Abstract: Structural evolution, sintering behavior, and microwave dielectric properties of (1−x)Li{sub 2}TiO{sub 3} + xLiF (0.05 ≤ x ≤ 0.70) ceramics have been studied by X-ray diffraction (XRD), Scanning Electron Microscopy (SEM), Raman spectra, thermal dilatometry and microwave resonant measurement at the frequency of about 7–11 GHz. The results show that Li{sub 2}TiO{sub 3} can form limited solid solution with LiF (x ≤ 0.4) and LiF second phase appeared when x{sup 3}0.5. The structure of the solid solution transformed from ordered monoclinic phase (β-Li{sub 2}TiO{sub 3} (ss)) to disordered cubic rock salt (α-Li{sub 2}TiO{sub 3} (ss)) when x{sup 3}0.15. The presence of short range ordering was confirmed for the cubic phase. The sinterability was considerably improved by doping with LiF. Densified ceramics with about 95–98% theoretical density could be obtained for the doped compositions after sintering at 900–1150 °C/2 h. An optimized microwave dielectric properties with ε{sub r} of ∼23.6, Q × f of ∼108,000 GHz and τ{submore » f} of ∼4.2 ppm/°C could be obtained for the x = 0.1 composition after sintering at 1100 °C/2 h.« less
Authors:
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Publication Date:
OSTI Identifier:
22341715
Resource Type:
Journal Article
Resource Relation:
Journal Name: Materials Research Bulletin; Journal Volume: 48; Journal Issue: 8; Other Information: Copyright (c) 2013 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; CERAMICS; DENSITY; DIELECTRIC PROPERTIES; DILATOMETRY; DOPED MATERIALS; LITHIUM FLUORIDES; LITHIUM TITANATES; MICROSTRUCTURE; MONOCLINIC LATTICES; RAMAN SPECTRA; SALT DEPOSITS; SCANNING ELECTRON MICROSCOPY; SINTERING; SOLID SOLUTIONS; X-RAY DIFFRACTION