【作者】 丁银忠；

【导师】 喻佑华；

【作者基本信息】 景德镇陶瓷学院 ， 材料学， 2007， 硕士

【摘要】 随着微波技术的高速发展，需要具有低温烧结的高性能的微波介质材料来满足微波元器件微型化发展要求。钛酸锌陶瓷中偏钛酸锌具有谐振频率温度系数小、介电常数高、品质因数高等优良微波介电性能，同时具有较低的烧结温度（约1100℃），是一种有望很快实用化的微波介质材料；但是在950℃以上，钛酸锌陶瓷中微波介电性能较好的钛铁矿型ZnTiO₃相易受热发生分解反应生成微波介电性能较差的尖晶石型Zn₂TiO₄相和金红石相，利用传统的固相烧结法很难制备出单一相ZnTiO₃陶瓷材料。能否提高钛酸锌陶瓷中ZnTiO₃相的热稳定性，是制备优良微波介电性能低温共烧钛酸锌陶瓷材料的关键。本文针对这一难题从以下几个方面展开研究。对钛酸锌陶瓷起始原料进行TG／DTA综合热分析，初步确定样品的烧结温度曲线，钛酸锌陶瓷中六方ZnTiO₃相的热分解温度为950℃；通过对不同烧结温度和不同钛锌摩尔配比下钛酸锌陶瓷样品进行XRD，SEM分析，确定钛酸锌陶瓷中六方钛铁矿型ZnTiO₃相的最佳合成温度为850℃，最佳合成钛锌摩尔配比为1∶1。对ABO₃铁钛矿型六方ZnTiO₃相中A位Zn²⁺进行Mg²⁺和Co²⁺双离子复合取代研究，利用TG／DTA、XRD和SEM等测试技术研究Mg²⁺和Co²⁺双离子复合掺杂量的变化对六方ZnTiO₃相的热稳定性和钛酸锌陶瓷物相及显微结构的影响。研究表明：当Mg²⁺和Co²⁺双离子复合掺杂量为0.1mol时，六方ZnTiO₃相的热分解温度约增加70℃；适量的双元复合取代能够提高六方ZnTiO₃相的热稳定温度，细化ZnTiO₃晶粒及促进ZnTiO₃烧结致密化程度的提高。研究双元复合取代Zn²⁺离子钛酸锌陶瓷的微波介电性能发现：微波介电性能较好的Zn_0.93(Mg_1／2Co_1／2)_0.07TiO₃微波介质材料能在990℃下烧结，其微波介电常数ε_r，约为25，品质因数Qf值约为40000GHz，谐振频率温度系数τ_f=0。对ABO₃铁钛矿型六方ZnTiO₃相中B位Ti⁴⁺分别进行Zr⁴⁺、Sn⁴⁺离子取代研究，利用TG／DTA、XRD和SEM等测试技术研究Zr⁴⁺、Sn⁴⁺离子掺杂量的变化对钛酸锌陶瓷中六方ZnTiO₃相的热稳定性和钛酸锌陶瓷物相及显微结构的影响。研究表明：当掺杂量为0.05mol时，Zr⁴⁺和Sn⁴⁺离子都能够与六方相ZnTiO₃形成固溶体，六方ZnTiO₃相的热分解温度约增加40℃，增大ZnTiO₃晶粒，但降低ZnTiO₃陶瓷的烧结致密度程度。研究Zr⁴⁺和Sn⁴⁺分别取代Ti⁴⁺离子钛酸锌陶瓷的微波介电性能发现：在1150℃烧结温度下，能够制备出微波介电性能为：ε_r=29.5、Qf=3620GHz、τ_f=+43（ppm／℃）的ZnTi_0.97Zr_0.03O₃微波介质材料；在1100℃烧结温度下，能够制备出微波介电性能为：ε=29.75、Qf=4539GHz、τ_f=+21（ppm／℃）的ZnTi_0.95Sn_0.05O₃微波介质材料。更多还原

【Abstract】 With the rapid development of microwave communication technology, high performance microwave dielectric ceramics, which can be sintered at low temperature, are required by the miniaturization of microwave components. In the zinc titanate ceramics, zinc metatitanate behaves excellent microwave dielectric properties, high dielectric constant, high quality factors and stable temperature coefficient of resonant frequency, and it can be sintered at lower temperature （1100℃） than traditional microwave dielectric ceramics. So this system microwave dielectric materials may be put into industrial production quickly. But zinc metatitanate, ZnTiO₃, decomposes into zinc orthotitanate and rutile at 945℃, the preparation of pure ZnTiO₃ has been unsuccessful by conventional solid-state reaction. Enhancing the thermal stability of zinc metatitanate, is the key to prepare low temperature co-fired microwave dielectric material with the excellent microwave dielectric properties. To this question, some studies will be carried out as follows.After the synthesis thermal analysis to the raw material of the zinc titanate ceramics, and has preliminary determined the sintering temperature curve of the zinc titanate ceramics, the phase transition temperature of zinc metatitanate was 950℃. The microstructure of this ceramics, which sintered at different temperature or different molar ratios of Ti/Zn, was studied by X-ray diffraction analysis and scanning electron microscopy, and it was found that the optimum temperature of synthesizing zinc metatitanate at approximately 850℃, and the specimens have optimum of synthesizes zinc metatitanate when the molar ratio of Ti/Zn is 1:1.Using the similar ionic radius Mg²⁺and Co²⁺ substituting the Zn²⁺ of zinc titanate, where Zn²⁺at the A-site of ilmenite-type titanates. The microstructure of this ceramics, which has different amounts of additions, was studied by X-ray diffraction analysis and scanning electron microscopy, and it was found that the phase transition temperature of zinc metatitanate was increased for 70℃; the proper amounts of double ionic substitution can enhance the thermally stable temperature of zinc metatitanate crystals, and also decreased the grain size of zinc metatitanate crystals, and increased the densification of zinc metatitanate ceramics. After systematic studies, we have achieved microwave dielectric material Zn_0.93(Mg_1/2Co_1/2)_0.07TiO₃ possessing excellent properties which can be sintered at approximately 990℃. The dielectric properties of the samples are indicated as below: dielectric constant values saturating at 25, the Qf value being 40000GHz, the temperature coefficient of resonant frequency being 0 ppm/℃_-1.The ionic radius of Zr₄₊and Sn_{4^</sub> are very similar to the ionic radius of Ti4+, using the similar of ionic radius Zr⁴⁺or Sn⁴⁺ substituting Ti⁴⁺of Zinc metatitanate, where Yi⁴⁺ at the B-site of ilmenite-type titanates. The microstructure of this ceramics, which has different amounts of additions, was studied by X-ray diffraction analysis and scanning electron microscopy, and it was found that the solubility limit of zirconium ions in ZnTiO3 was close to 0.05, The solubility limit of stannum ions in ZnTiO3 was same, The proper amounts of Zr4+or Sn4+ ionics substitution all can increase the phase transition temperature of Zinc metatitanate for 40℃, and changes the microstructure of the zinc titanate ceramics. After systematic studies, we have achieved microwave dielectric material ZnTi0.97Zr0.03O3 possessing excellent properties which can be sintered at approximately 1150℃. The dielectric properties of the samples are indicated as below: dielectric constant values saturating at 29.5, the Qf value being 3620GHz, the temperature coefficient of resonant frequency was 43 ppm/℃^-1; we also achieved microwave dielectric material ZnTi0.95Sn0.05O3 possessing excellent properties which can be sintered at approximately 1100℃. The dielectric properties of the samples are indicated as below: dielectric constant values saturating at 29.75, the Qf value being 4539GHz, the temperature coefficient of resonant frequency being 21 pprn/℃^-1.}更多还原