论文总字数：25907字

摘 要

微波介质陶瓷在现代通信和微波技术等众多领域中扮演着重要的角色。本论文介绍了微波介质陶瓷的发展历史、分类、介电性能参数、影响因素、制备方法、研究进展等内容，并选用MgMoO₄作为研究对象。MgMoO₄属于黑钨矿结构，烧结温度比白钨矿型结构低，符合低温共烧陶瓷(LTCC)技术的应用条件。

本论文讨论了钼酸镁陶瓷的烧结性能、介电性能与预烧温度、烧结温度之间的关系，研究表明，当预烧温度为750 ℃，烧结温度为950 ℃，保温3h时性能最佳，为ε_r = 7.07，Q×f = 49149 GHz，τ_f = -67 ppm/℃。由于MgMoO₄陶瓷谐振频率温度系数比较大，本论文通过磁性离子（Mn，Ni，Co）掺杂来调节钼酸镁陶瓷的介电性能。研究得到最佳性能为：T_s = 950 ℃，x = 0.05，Mg_0.95Mn_0.05MoO₄的ε_r = 7.04，Q×f = 47961 GHz，τ_f = -55 ppm/℃；T_s = 925 ℃，x = 0.05，Mg_0.95Ni_0.05MoO₄的ε_r = 7.08，Q×f = 42775 GHz，τ_f =-52 ppm/℃；T_s = 975 ℃，x = 0.05，Mg_0.99Co_0.01MoO₄的ε_r = 7.02，Q×f = 59418 GHz，τ_f = -68 ppm/℃。Mn和Ni掺杂可以降低τ_f，Co掺杂可以提高Q×f值。

关键词：微波介质陶瓷 介电性能 磁性离子 谐振频率温度系数

Performance Regulation of Magnetic Ion Doping on Magnesium Molybdate Microwave Dielectric Ceramics

Abstract

Microwave dielectric ceramics play an important role in many fields of modern communication and microwave technology. This paper introduces the history, classification, dielectric performance, factors, preparation methods, research progress of microwave dielectric ceramics, and selects MgMoO₄ as the research object. MgMoO₄ has wolframite structure, and the sintering temperature is lower than that of the scheelite structure ceramics, which is in accordance with the application conditions of the Low Temperature Co-fired Ceramic (LTCC) technology.

In this paper, the relationship between sintering performance, dielectric properties, calcined temperature and sintering temperature of MgMoO₄ ceramics is discussed. Research shows that when calcined at 750 ℃, and sintered at 950 °C for 3 h, the MgMoO₄ ceramics obtain the best properties: ε_r = 7.07, Q×f = 49149 GHz, τ_f = -67 ppm/°C. Since the resonance frequency temperature coefficient ceramic MgMoO₄ is relatively large, the dielectric properties of the present paper is adjusted by doping magnetic ions (Mn, Ni, Co). The best performance are as follows: T_s = 950 ℃, x = 0.05, Mg_0.95Mn_0.05MoO₄: ε_r =7.04, Q×f = 47961 GHz, τ_f = -55 ppm/℃; T_s = 975 ℃, x=0.01, Mg_0.99Co_0.01MoO₄: ε_r = 6.94, Q×f = 54198 GHz, τ_f = -63 ppm/℃; T_s = 925 ℃, x=0.05, Mg_0.95Ni_0.05MoO₄: ε_r =7.08, Q×f = 42775 GHz, τ_f = -52 ppm/℃. Mn and Ni doping can reduce τ_f, and Co doping can increase Q×f value.

Key words: Microwave dielectric ceramic; Dielectric properties; Magnetic ions; Resonant frequency temperature coefficient

目 录

摘 要 I

Abstract II

第一章 绪论 1

1.1引言 1

1.2 微波介质陶瓷的简介 1

1.2.1 发展历史 1

1.2.2 介电性能参数 2

1.2.3 微波介质陶瓷的分类 3

1.2.4 微波介质陶瓷的制备 4

1.2.5 低温共烧陶瓷 5

1.3 课题的背景与研究内容 8

1.3.1 课题的提出背景 8

1.3.2 课题研究内容 8

第二章 实验方案 9

2.1 实验原料与设备 9

2.1.1 实验原料 9

2.1.2 实验仪器 9

2.2 实验方法 10

2.2 样品的性能测试 11

2.2.1 体积密度测试 12

2.2.2 晶相组成测试 12

2.2.3 介电性能测试 12

2.2.4 显微结构分析 12

第三章 实验结果及分析 13

3.1 MgMoO₄微波介质陶瓷的性能 13

3.1.1 物相组成分析 13

3.1.2 烧结性能分析 13

3.1.3 微观形貌分析 14

3.1.4 介电性能分析 15

3.1.5 保温时间对介电性能的影响 17

3.2 Mg_1-xMn_xMoO₄微波介质陶瓷性能分析 17

3.2.1 物相组成观察分析 17

3.2.2 烧结性能分析 18

3.2.3 微观形貌分析 19

3.2.4 介电性能分析 20

3.3 Mg_1-xNi_xMoO₄微波介质陶瓷性能分析 22

3.3.1 物相组成分析 22

3.3.2 烧结性能的分析 23

3.3.4 介电性能分析 25

3.4 Mg_1-xCo_xMoO₄微波介质陶瓷性能分析 27

3.4.1 物相组成分析 27

3.4.2 烧结性能的分析 29

3.4.3 介电性能分析 29

第四章 实验结论 33

4.1 MgMoO₄微波介质陶瓷性能分析 33

4.2 Mg_1-xM_xMoO₄（M=Mn，Ni，Co）微波介质陶瓷性能分析 33

参考文献 34

致谢 37

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