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<p>The effects of Mn<sup>2</sup>⁺ substitution on the sintering behavior and microwave dielectric properties of Li<sub>2</sub>MgSiO<sub>4</sub> ceramics were systematically investigated. Li<sub>2</sub>Mg<sub>1-x</sub>Mn<sub>x</sub>SiO₄ ceramics (x = 0–0.10) were prepared by a modified solid-state reaction method. X-ray diffraction combined with Rietveld refinement confirms that all samples retain a monoclinic Li<sub>2</sub>MgSiO<sub>4</sub> structure (space group P2₁/c) without detectable secondary phases within the investigated composition range, indicating that Mn<sup>2</sup>⁺ successfully substitutes for Mg<sup>2</sup>⁺ in the lattice. Mn<sup>2</sup>⁺ substitution effectively reduces the optimum sintering temperature and promotes densification. The composition with x = 0.04 sintered at 1100&#xa0;°C for 1&#xa0;h exhibits the highest relative density (96.42%) and the best microwave dielectric properties, with <InlineEquation ID="IEq1"> <EquationSource Format="TEX">\({ }\varepsilon_{r}\)</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mrow /> <msub> <mi>ε</mi> <mi>r</mi> </msub> </mrow> </math></EquationSource> </InlineEquation> = 5.93 (measured at 13.179&#xa0;GHz), <i>Q</i> × <i>f</i> = 34,845&#xa0;GHz, and <InlineEquation ID="IEq2"> <EquationSource Format="TEX">\(\tau_{f}\)</EquationSource> <EquationSource Format="MATHML"><math> <msub> <mi>τ</mi> <mi>f</mi> </msub> </math></EquationSource> </InlineEquation> =  − 60.6&#xa0;ppm/°C. SEM observations reveal that moderate Mn<sup>2</sup>⁺ substitution improves grain uniformity and densification, whereas excessive substitution leads to abnormal grain growth and degraded dielectric performance. Polarizability analysis further indicates that the increase in dielectric permittivity mainly originates from the enhanced intrinsic polarization induced by Mn<sup>2</sup>⁺ substitution. These results demonstrate that Mn<sup>2</sup>⁺ substitution is an effective strategy to improve the sintering behavior and optimize the microwave dielectric properties of Li<sub>2</sub>MgSiO<sub>4</sub> ceramics.</p>

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Effect of Mn2⁺ substitution on the sintering behavior and microwave dielectric properties of Li2Mg1-xMnxSiO4 ceramics

  • 期刊论文

  • 发表日期：

    2026年4月18日

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  • Huangping Yang,
  • Yang Lu,
  • Jie Xu,
  • Heng Miao,
  • Hongqing Zhou,
  • Huifen Lu,
  • Bo Zhang

摘要

The effects of Mn2⁺ substitution on the sintering behavior and microwave dielectric properties of Li2MgSiO4 ceramics were systematically investigated. Li2Mg1-xMnxSiO₄ ceramics (x = 0–0.10) were prepared by a modified solid-state reaction method. X-ray diffraction combined with Rietveld refinement confirms that all samples retain a monoclinic Li2MgSiO4 structure (space group P2₁/c) without detectable secondary phases within the investigated composition range, indicating that Mn2⁺ successfully substitutes for Mg2⁺ in the lattice. Mn2⁺ substitution effectively reduces the optimum sintering temperature and promotes densification. The composition with x = 0.04 sintered at 1100 °C for 1 h exhibits the highest relative density (96.42%) and the best microwave dielectric properties, with \({ }\varepsilon_{r}\) ε r  = 5.93 (measured at 13.179 GHz), Q × f = 34,845 GHz, and \(\tau_{f}\) τ f  =  − 60.6 ppm/°C. SEM observations reveal that moderate Mn2⁺ substitution improves grain uniformity and densification, whereas excessive substitution leads to abnormal grain growth and degraded dielectric performance. Polarizability analysis further indicates that the increase in dielectric permittivity mainly originates from the enhanced intrinsic polarization induced by Mn2⁺ substitution. These results demonstrate that Mn2⁺ substitution is an effective strategy to improve the sintering behavior and optimize the microwave dielectric properties of Li2MgSiO4 ceramics.