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>Novel ultra-low temperature co-fired microwave dielectric ceramic at 400 degrees and its chemical compatibility with base metal
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Novel ultra-low temperature co-fired microwave dielectric ceramic at 400 degrees and its chemical compatibility with base metal
A novel NaAgMoO4 material with spinel-like structure was synthesized by using the solid state reaction method and the ceramic sample was well densified at an extreme low sintering temperature about 400°C. Rietveld refinement of the crystal structure was performed using FULLPROF program and the cell parameters are a = b = c = 9.22039 Å with a space group F D −3 M (227). High performance microwave dielectric properties, with a permittivity ~7.9, a Qf value ~33,000 GHz and a temperature coefficient of resonant frequency ~−120 ppm/°C, were obtained. From X-ray diffraction (XRD) and Energy Dispersive Spectrometer (EDS) analysis of the co-fired sample, it was found that the NaAgMoO4 ceramic is chemically compatible with both silver and aluminum at the sintering temperature and this makes it a promising candidate for the ultra-low temperature co-fired ceramics technology. Analysis of infrared and THz spectra indicated that dielectric polarizability at microwave region of the NaAgMoO4 ceramic was equally contributed by ionic displasive and electronic polarizations. Its small microwave dielectric permittivity can also be explained well by the Shannon's additive rule.
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机译:利用固态反应方法合成了一种新型的尖晶石状NaAgMoO4材料,并在约400℃的极低烧结温度下对陶瓷样品进行了致密化。使用FULLPROF程序对晶体结构进行Rietveld精炼,晶胞参数为a = b = c = 9.22039Å,空间群F D -3 M(227)。获得了高性能的微波介电性能,介电常数约为7.9,Qf值约为33,000 GHz,谐振频率的温度系数约为-120 ppm /°C。通过对共烧样品的X射线衍射(XRD)和能量分散光谱仪(EDS)分析,发现NaAgMoO4陶瓷在烧结温度下与银和铝化学相容,这使其成为有希望的候选材料。超低温共烧陶瓷技术。红外和太赫兹光谱分析表明,NaAgMoO4陶瓷在微波区域的介电极化率同样受离子迁移和电子极化的影响。其较小的微波介电常数也可以通过香农的加性法则很好地解释。
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