Phase transition, electrical and dielectric properties of novel ultra-low sintering temperature NaAlMo2O8 ceramic for application in patch antenna

IF 4.9 2区化学 Q2 CHEMISTRY, PHYSICAL

Colloids and Surfaces A: Physicochemical and Engineering Aspects Pub Date : 2025-02-03 DOI:10.1016/j.colsurfa.2025.136325

Xiangyu Xu , Yiyun Zhang , Jialun Du , Haitao Wu , Jie Zhang , Yunzhou Shi

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引用次数: 0

Abstract

This study synthesized a novel low-temperature sintered NaAlMo₂O₈ (NAM) ceramic using the conventional solid-state method. XRD and Rietveld refinement analyses confirmed that the NAM ceramic exhibited a monoclinic structure (space group C2/c (No. 15)) in the temperature range of 620 °C to 660 °C. Density measurements and SEM revealed that the NAM ceramics possessed a dense microstructure with optimal grain distribution. The electrical characteristics of NAM ceramics were examined through complex impedance spectroscopy, while the potential migration pathways of Na⁺ and O²⁻ were investigated using the bond-valence method. The best performance was observed at a sintering temperature of 650 °C, with ε_r= 7.81, Q×f = 38,213 GHz (at 10.56 GHz), τ_f = −45.43 ppm/°C. Furthermore, Raman spectroscopy and far-IR reflection spectroscopy were used to investigate the lattice vibrational modes of the NAM ceramic. Notably, far-IR reflection spectroscopy indicated that polarization in the NAM ceramic primarily arises from phonon absorption in the low-frequency region. According to P-V-L theory, it was found that in the NAM ceramic system, Al-O bonds predominantly influence ε_r, while Mo-O bonds significantly affect Q×f and τ_f. The formation energies of intrinsic point defects in NAM ceramic were computed using the GULP. Finally, a patch antenna for S-band applications was fabricated using this NAM ceramic, highlighting its potential for use in Sub-6 GHz frequency bands. Due to phase transformation characteristics at elevated temperatures, NAM ceramics may also serve as a promising electrolyte material for SOFCs.

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来源期刊

Colloids and Surfaces A: Physicochemical and Engineering Aspects 化学-物理化学

CiteScore

8.70

自引率

9.60%

发文量

2421

审稿时长

56 days

期刊介绍： Colloids and Surfaces A: Physicochemical and Engineering Aspects is an international journal devoted to the science underlying applications of colloids and interfacial phenomena. The journal aims at publishing high quality research papers featuring new materials or new insights into the role of colloid and interface science in (for example) food, energy, minerals processing, pharmaceuticals or the environment.