Ma Xiaomeng,Li Congyi,Fan Zijia,Wu Haitao,Zhang Yuping,Zhang Zhiliang
Low temperature-sintered ceramics Nd 2 Zr 3 (MoO 4 ) 9 were successfully prepared via reaction-sintering method. The sintering behavior, microwave dielectric properties, crystal structure, and microstructure were analyzed systematically. XRD and Rietveld refinement results revealed that all samples formed a pure trigonal structure phase with the space group of R-3c. Density determination showed that ceramics possessed the highest relative density when sintered at 800 °C for 6 h. SEM image further confirmed that ceramics possessed dense and homogeneous microstructure at the optimum sintering temperature 800 °C. Far infrared spectra analysis showed the structural phonon oscillation at infrared region played an important role in polarization. Nd 2 Zr 3 (MoO 4 ) 9 ceramics obtained the optimum microwave dielectric properties of ε r = 10.01, Q × f = 55,923 GHz, τ f = − 13.81 ppm/ °C when sintered at 800 °C for 6 h.
In this work, Nd 2 (Zr 1- x Sn x ) 3 (MoO 4 ) 9 (0.02 ≤ x ≤ 0.1) (NZSM) ceramics were successfully obtained through conventional solid-state route. Phase analysis, microstructure, and properties were investigated scientifically by XRD , SEM, and network analyzer, respectively. XRD results revealed that all samples with different substitution amounts of Sn 4+ formed the pure phase with R-3c space group. The permittivity was related to the polarizability and the bond of Zr2-O5, the bond of Nd-O2 possessed a positive influence on Q×f . The reduced octahedral distortion and increased bond energy made the temperature coefficient more stable. Infrared reflection spectrum results showed that the permittivity was mainly caused by the absorption of phonon oscillation. The optimum properties ( ε r = 10.34, Q×f = 74,795 GHz, τ f = −13.55 ppm/°C) were obtained when x = 0.02 sintered at 750 °C.
Low-temperature sintered microwave dielectric ceramics are gaining increasing attention for next-generation wireless communication systems, particularly within the 6 G frequency range. However, materials that simultaneously exhibit ultra-low dielectric loss and low sintering temperatures remain scarce. In this study, Nd 2 [Zr 1-X (Bi 0.5 Ta 0.5 ) X ] 3 (MoO 4 ) 9 ceramics were prepared via a conventional solid-state reaction method and exhibited a single-phase structure with a trigonal symmetry (space group R 3 ¯ C, No. 167). The optimal sample at x = 0.11 sintered at 750 ℃ showed excellent performance: ε r = 11.4, Q×f = 186,300 ± 8900 GHz, and τ f = –42.9 ppm/℃. The elevated Q×f value is chiefly ascribed to increased lattice energy, with its variation more plausibly arising from intrinsic effects within the material. The dielectric constant (εᵣ), analyzed using the Clausius–Mosotti equation, was predominantly influenced by ionic polarizability. According to P–V–L theory, the effective bond strength f iNd–O played a major role in determining εᵣ, while τ f was governed by the bond energy and thermal expansion behavior of Mo–O bonds. Raman spectroscopy further confirmed the structure–property relationships. These results suggest that B-site substitution with (Bi 0.5 Ta 0.5 ) 4+ not only promotes densification and increases lattice energy, but also maintains thermal stability, thereby enhancing Q×f without compromising τ f . This system offers strong potential for integration into future microwave dielectric components.
危险品化学品经营许可证（带存储）