Influence of Ca _xSr_1−x(0⩽x⩽1) Substitution for Zn on Microwave Dielectric Properties of Li₂ZnTi₃O₈ Ceramic as Temperature Stable Materials

Abstract

A temperature stable Li₂Zn_0.95(Sr _xCa_1−x)_0.05Ti₃O₈ (0⩽x⩽1) ceramics were fabricated using a conventional solid-state route sintered at 1100 °C for 4 h. The XRD results indicate that the main phase Li₂ZnTi₃O₈ and secondary phase including Sr₁Ca_1−xTiO₃ (0⩽x⩽1) solid solution and TiO₂ co-exist in composite and form a stable composite system when the (Ca _xSr_1−x) (0⩽x⩽1) substitutes for Zn of Li₂ZnTi₃O₈ ceramic. As x is increased from 0 to 1, the relative permittivity (ε _r) increases from 26.65 to 27.12, and the quality factor (Q×f) increases from 63 300 to 66 600 GHz. With the increased of x, the temperature coefficient of resonant frequency (τ _f) increases from 0.27 to 8.23 ppm/°C, and then decreases to 3.51 ppm/°C. On the whole, the Li₂Zn_0.95(Sr _xCa_1−x)_0.05Ti₃O₈ (0⩽x⩽1) ceramics show excellent comprehensive properties of middle ε _r = 25–27, higher Q×f ⩾ 60000 GHz and τ _f ⩽±8.5 ppm/°C.

Keywords

Li₂Zn_0.95(Sr _xCa_1−x)_0.05Ti₃O₈ (0⩽x⩽1) / microwave dielectric properties / temperature stable materials / substitution

References

[1] Ravi GA, Azough F, Freer R. Structure and Microwave Dielectric Properties of Ca_0.7Ti_0.7La_0.3(Al_0.3−xGa_x)O3 Ceramics[J]. Adv. Appl. Ceram., 2012, 111: 398-403.

[2] Mane SM, Tirmali PM, Kadam SL, et al. Microwave-assisted Sintering and Improved Dielectric, Ferroelectric Properties of 0.5[(Ba_0.7Ca_0.3) TiO₃]-0.5[Ba(Zr_0.2T_i0.8)O₃] Lead-free Ceramics[J]. Adv. Appl. Ceram., 2017, 116: 325-332.

[3] Sebastian MT, Ubic R, Jantunen H. Low-loss Dielectric Ceramic Materials and Their Properties[J]. Int. Mater. Rev., 2015, 60: 392-412.

[4] Lee ST, Jo YH, Kim HE, et al. Grain Boundary Segregation and Microwave Dielectric Properties of Low Loss Mg_1.5Zn_0.5SiO₄ Ceramics Containing Bi₂O₃[J]. Adv. Appl. Ceram., 2010, 109: 367-372.

[5] George S, Sebastian MT. Synthesis and Microwave Dielectric Properties of Novel Temperature Stable High Q, Li₂ATi₃O₈ (A=Mg, Zn) Ceramics[J]. J. Am. Ceram. Soc., 2010, 93: 2 164-2 166.

[6] Bari M, Nassaj ET, Armaki HT. Role of Nano-and Micron-Sized Particles of TiO₂ Additive on Microwave Dielectric Properties of Li₂Zn-Ti₃O₈-4wt% TiO₂ Ceramics[J]. J. Am. Ceram. Soc., 2013, 96: 3 737-3 741.

[7] Ren HS, Hao L, Peng HY, et al. Investigation on Low-temperature Sinterable Behavior and Tunable Dielectric Properties of BLMT Glass-Li₂ZnTi₃O₈ Composite Ceramics[J]. J. Eur. Ceram. Soc., 2018, 38: 3 498-3 504.

[8] George S, Sebastian MT. Microwave Dielectric Properties of Novel Temperature Stable High Q Li₂Mg_1−xZn_xTi₃O₈ and Li₂A_1−xCa_xTi₃O₈ (A = Mg, Zn) Ceramics[J]. J. Eur. Ceram. Soc., 2010, 30: 2 585-2 592.

[9] Wise PL, Reaney IM, Lee WE, et al. Structure-microwave Property Relations in (Sr_xCa_(1−x)) _n+1Ti_nO_3n+1[J]. J. Eur. Ceram. Soc., 2001, 21: 1 723-1 726.

[10] Wise PL, Reaney IM, Lee WE, et al. Structure-microwave Property Relations of Ca and Sr Titanates[J]. J. Eur. Ceram. Soc., 2001, 21: 2 629-2 632.

[11] Wu HT, Kim ES. Correlations between Crystal Structure and Dielectric Properties of High-Q Materials in Rock-salt Structure Li₂O-MgO-BO₂ (B = Ti, Sn, Zr) Systems at Microwave Frequency[J]. Rsc. Adv., 2016, 64: 47 443-47 453.

[12] Xie TY, Zhang LZ, Ren HS, et al. A novel Temperature-stable and Low-loss Microwave Dielectric Using Ca_0.8S_0.2TiO₃-modified Li₂Mg₃ TiO₆ Ceramics[J]. J. Mater. Sci.: Mater Electron, 2017, 28: 13 705-13 709.

[13] Ren HS, Jiang SH, Dang MZ, et al. Investigating on Sintering Mechanism and Adjustable Dielectric Properties of BLMT Glass/Li₂Zn₃Ti₄O₁₂ Composites for LTCC Applications[J]. J. Alloy. Compd., 2018, 740: 1 188-1 196.

[14] Fukuda K, Kitoh R, Awai I. Microwave Characteristics of Mixed Phases of BaTi₄O₉-BaPr₂Ti₄O₁₂ Ceramics[J]. J. Mater. Sci., 1995, 30: 1 209-1 216.