کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
5438844 1398188 2017 5 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Effect of substituting Ti sites with (MgxNb0.8-0.4x)4+ on the microwave dielectric properties of Mg2TiO4 ceramics
موضوعات مرتبط
مهندسی و علوم پایه مهندسی مواد سرامیک و کامپوزیت
پیش نمایش صفحه اول مقاله
Effect of substituting Ti sites with (MgxNb0.8-0.4x)4+ on the microwave dielectric properties of Mg2TiO4 ceramics
چکیده انگلیسی
The microwave dielectric properties of Mg2Ti0.95(MgxNb0.8-0.4x)0.05O4 (0 ≤ x ≤ 1) ceramics were investigated based on the structural characteristics obtained by Rietveld refinement. Specimens with 0 ≤ x ≤ 0.75 showed a single-phase inverse spinel structure with cubic symmetry. The average ionic radius increased with increase in x because of the larger ionic radius of Mg2+ (0.72 Å) than Nb5+ (0.64 Å). However, the lattice parameter decreased because of an increase in the bond valence of the Ti site, which in turn led to an increase in the packing fraction of the unit cell. The quality factor (Qf) of the specimens increased with increase in x up to x = 0.75 and then decreased because of the inclusion of secondary phases, such as MgTiO3 and Mg-rich spinels. For single-phase specimens, the Qf value depended on the packing fraction of the unit cell. Despite the higher ionic polarizability of Nb5+ (3.97 Å) than Mg2+ (1.32 Å), the dielectric constants remained constant due to the increase of relative density of the specimens with x. The temperature coefficients of the resonant frequency of all the specimens were similar.
ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Ceramics International - Volume 43, Supplement 1, August 2017, Pages S321-S325
نویسندگان
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