Compositional design, structure stability, and microwave dielectric properties in Ca3MgBGe3O12 (B = Zr, Sn) garnet ceramics with tetravalent cations on B-site. Issue 4 (15th February 2022)

• Record Type: Journal Article
• Authors: Mei, Hongrong; Zhang, Liangbin; Li, Chunchun; Rao, Zhenggang; Shu, Longlong
• Is Part Of: Ceramics international. Volume 48:Issue 4(2022)
• Page Start: 4658
• Page End: 4664
• Publication Date: 2022-02-15
• Subjects: Garnet -- Ceramics -- Solid state reaction -- Dielectric properties -- Packing fraction -- Infrared reflectivity spectra; Ceramics -- Periodicals; Céramique industrielle -- Périodiques; Ceramics; Periodicals; Electronic journals; 666
• DOI: 10.1016/j.ceramint.2021.11.001
• Languages: English
• ISSNs: 0272-8842

Abstract

Abstract: Two garnet-structured Ca3 MgBGe3 O12 (B = Zr, Sn) ceramics with tetravalent cations at B-site were prepared by conventional solid state reaction. The crystal structure, microstructure evolution, and microwave dielectric performance were investigated using X-ray powder diffraction, Rietveld refinement, scanning electron microscopy, Raman spectroscopy, and infrared spectroscopy techniques. Dense Ca3 MgZrGe3 O12 and Ca3 MgSnGe3 O12 ceramics were obtained at sintering temperatures of 1420 and 1400 °C, respectively. The dielectric constant, unloaded quality factor, and temperature coefficient of resonance frequency of Ca3 MgZrGe3 O12 were 10.80 ± 0.2; 79, 600 ± 1000 GHz ( f = 12.61 GHz); and −66.8 ± 1 ppm/°C, respectively, and the corresponding values for Ca3 MgSnGe3 O12 were 9.68 ± 0.2; 83, 400 ± 1000 GHz ( f = 14.19 GHz); and −57.9 ± 1 ppm/°C, respectively. The dielectric performances of the two ceramics were compared by analyzing the ionic polarizability, packing fraction, and bond valence. The intrinsic dielectric properties were predicted by fitting the infrared reflectivity spectra.