New high-quality microwave dielectric ceramics Mg₂NdNbO₆ were prepared by conventional solid-state sintering method. The phases, micro-structures and microwave dielectric properties of Mg₂NdNbO₆ ceramics were investigated at sintering temperature in the range of 1275°C-1400°C. The X-ray diffraction patterns showed that the peaks of the compounds were attributed to two phases, including the main crystalline phase of NdNbO₄ that was indexed as the monoclinic phase and MgO as the second phase. Well-developed microstructures of Mg₂NdNbO₆ ceramics can be achieved, and the grain size reached the maximum value (1.63 μm) at 1375°C. As the sintering temperature increased, the dielectric constant, temperature coefficient of resonant frequency and apparent density remained almost unchanged, however, the significant change in the quality factor was observed. At 1375°C, Mg₂NdNbO₆ ceramics possessed excellent microwave dielectric properties: ε_r = 16.22, Q × f = 116 000 GHz and τ_f = −30.96 ppm/°C.

中文翻译：

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新型优质Mg2NdNbO6陶瓷的合成及微波介电性能

采用传统的固态烧结法制备了新型高质量微波介电陶瓷Mg ₂ NdNbO ₆。研究了Mg ₂ NdNbO ₆陶瓷在1275°C-1400°C的烧结温度下的相，微结构和微波介电性能。X射线衍射图表明，化合物的峰归因于两个相，包括被标记为单斜晶相的NdNbO ₄主晶相和被称为第二相的MgO。Mg ₂ NdNbO _6的精细组织可以制成陶瓷，并且在1375°C下晶粒尺寸达到最大值（1.63μm）。随着烧结温度的升高，介电常数，共振频率的温度系数和表观密度几乎保持不变，但是，观察到品质因数的显着变化。在1375°C下，Mg ₂ NdNbO ₆陶瓷具有优异的微波介电性能：_εr = 16.22，Q × f = 116 000 GHz和_τf = -30.96 ppm /°C。