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Sintering behavior, structural phase transition, and microwave dielectric properties of La 1‐ x Z n x TiNbO 6‐x/2 ceramics
Author(s) -
Zhang Jian,
Zuo Ruzhong
Publication year - 2017
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.14934
Subject(s) - sintering , monoclinic crystal system , orthorhombic crystal system , materials science , ceramic , dielectric , microstructure , mineralogy , phase (matter) , analytical chemistry (journal) , microwave , crystal structure , crystallography , composite material , chemistry , physics , optoelectronics , organic chemistry , quantum mechanics , chromatography
La 1‐ x Z n x TiNbO 6‐x/2 ( LZTN ‐x) ceramics were prepared via a conventional solid‐state reaction route. The phase, microstructure, sintering behavior, and microwave dielectric properties have been systematically studied. The substitution of a small amount of Zn 2+ for La 3+ was found to effectively promote the sintering process of LTN ceramics. The corresponding sintering mechanism was believed to result from the formation of the lattice distortion and oxygen vacancies by means of comparative studies on La‐deficient LTN ceramics and 0.5 mol% ZnO added LTN ceramics ( LTN +0.005ZnO). The resultant microwave dielectric properties of LTN ceramics were closely correlated with the sample density, compositions, and especially with the phase structure at room temperature which depended on the orthorhombic‐monoclinic phase transition temperature and the sintering temperature. A single orthorhombic LZTN ‐0.03 ceramic sintered at 1200°C was achieved with good microwave dielectric properties of ε r ~63, Q×f ~9600 GHz (@4.77 GHz) and τ f ~105 ppm/°C. By comparison, a relatively high Q × f ~80995 GHz (@7.40 GHz) together with ε r ~23, and τ f ~−56 ppm/°C was obtained in monoclinic LTN +0.005ZnO ceramics sintered at 1350°C.