CN110668794B - 一种改善Li3Mg2SbO6陶瓷烧结特性和微波介电性能的方法 - Google Patents

一种改善Li3Mg2SbO6陶瓷烧结特性和微波介电性能的方法 Download PDF

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CN110668794B
CN110668794B CN201910985462.6A CN201910985462A CN110668794B CN 110668794 B CN110668794 B CN 110668794B CN 201910985462 A CN201910985462 A CN 201910985462A CN 110668794 B CN110668794 B CN 110668794B
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姚国光
裴翠锦
谭晶晶
李阳
任卫
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Abstract

本发明公开了一种改善Li3Mg2SbO6陶瓷烧结特性和微波介电性能的方法,采用传统固相工艺,通过在Li3Mg2SbO6基体中引入Sb位晶格缺陷,Sb位晶格缺陷及氧空位活化了其晶格结构,不仅可改善其烧结特性(抑制Li3Mg2SbO6陶瓷开裂、降低其烧结温度),而且可改善其微波介电性能(Q×f最高提升约170%),其介电常数为9.5~11.0,品质因数Q×f为41700~86300GHz,谐振频率温度系数为‑12.7~‑7.9ppm/℃。本发明方法所用原料来源丰富、成本低廉,制备工艺简单,有利于工业化生产,所得陶瓷材料可广泛应用于微波介质基板、滤波器、天线等微波器件的制造。

Description

一种改善Li3Mg2SbO6陶瓷烧结特性和微波介电性能的方法
技术领域
本发明属于电子陶瓷及其制造技术领域,具体涉及一种改善Li3Mg2SbO6陶瓷烧结特性和微波介电性能的方法。
背景技术
微波介质陶瓷是指应用于微波频段(300MHz~300GHz)电路中作为介质材料完成一种或多种功能的陶瓷材料。理想微波介质陶瓷具有合适的介电常数εr、高品质因数Q×f(良好频率选择性)和趋于零的谐振频率温度系数τf(高的热稳定性)。随着物联网技术的迅猛发展,特别是5G技术日趋成熟,5G技术必将加速物联网落地,实现“万物互联”,这对高频用微波介质材料性能提出了更高要求,要求其具有低εr、近零τf和高Q×f。因此,开发和研究应用于高频下的高性能(低εr、近零τf、高Q×f)微波介质陶瓷受到极大关注。
通常,对于某一单相材料体系来说,很难同时满足上述三个性能参数指标的要求,尤其是同时具有低εr、近零τf和高Q×f值。岩盐结构Li3Mg2SbO6是一种少有的同时具有低εr、近零τf值和较高Q×f值的新型微波介质材料,但该低εr微波介质陶瓷同时存在一些缺点:其一是烧结特性差(烧结后开裂、烧结温度高),其二单相Li3Mg2SbO6陶瓷制备工艺较复杂,使其无法满足实际应用需求。因此,改善 Li3Mg2SbO6陶瓷烧结特性和微波介电性能并简化制备工艺有利于实现Li3Mg2SbO6介质陶瓷的商用化。
发明内容
本发明所要解决的技术问题在于克服现有技术中Li3Mg2SbO6陶瓷烧结特性差 (开裂、烧结温度高)、制备工艺复杂的缺点,提供一种改善Li3Mg2SbO6陶瓷烧结特性和微波介电性能的方法。
解决上述技术问题所采用的技术方案由下述步骤组成:
1、按照Li3Mg2Sb1-xO6-δ的化学计量比,式中0.05≤x≤0.10,将原料Li2CO3、 MgO、Sb2O3加入球磨罐中,以锆球为磨球、无水乙醇为球磨介质,充分混合球磨6~10小时,80~100℃干燥。
2、将步骤1干燥后的混合物在850~900℃预烧2~6小时,得到预烧粉。
3、将步骤2得到的预烧粉加入球磨罐中,以锆球为磨球、无水乙醇为球磨介质,充分混合球磨6~10小时,80~100℃干燥。
4、向步骤3干燥后的预烧粉中加入质量分数为5%的聚乙烯醇水溶液进行造粒,过80~120目筛,用粉末压片机压制成圆柱形生坯。
5、将圆柱形生坯在1200~1275℃烧结1~10小时。
上述步骤1,优选0.09≤x≤0.10。
上述步骤2中,优选将步骤1干燥后的混合物在900℃预烧4小时。
上述步骤5中,优选将圆柱形生坯在1250℃烧结5小时。
本发明通过在Li3Mg2SbO6基体中引入Sb位晶格缺陷,不仅可改善其烧结特性 (抑制Li3Mg2SbO6陶瓷开裂、降低其烧结温度),而且可改善其微波介电性能(Q×f 最高提升约170%)。本发明方法所用原料来源丰富、成本低廉,制备工艺简单,所得陶瓷材料可广泛应用于微波介质基板、滤波器、天线等微波器件的制造。
附图说明
图1是实施例1~5制备的微波介质陶瓷的X射线粉末衍射图。
图2是对比例1制备的微波介质陶瓷的照片。
图3是实施例1制备的微波介质陶瓷扫描电镜图。
具体实施方式
下面结合附图和实施例对本发明进一步详细说明,但本发明的保护范围不仅限于这些实施例。
实施例1
1、按照Li3Mg2Sb0.9O6-δ的化学计量比称取原料Li2CO3 3.466g、MgO 2.472g和 Sb2O34.062g,将原料混合物与锆球、无水乙醇按质量比为1∶2∶2装入尼龙球磨罐中,充分混合球磨8小时,90℃干燥5小时。
2、将步骤1干燥后的混合物置于氧化铝坩埚内,在900℃预烧4小时,得到预烧粉。
3、将预烧粉装入尼龙球磨罐中,加入锆球和无水乙醇,预烧粉与锆球、无水乙醇的质量比为1∶2∶2,充分混合球磨8小时,90℃干燥5小时。
4、向步骤3干燥后的预烧粉中加入预烧粉质量5%的质量分数为5%的聚乙烯醇水溶液进行造粒,过120目筛,用粉末压片机在4MPa压力下将其压制成直径为 10mm、厚度为5mm的圆柱形生坯。
5、将圆柱形生坯在1250℃烧结5小时,制备成微波介质陶瓷。
实施例2
在实施例1的步骤1中,按照Li3Mg2Sb0.95O6-δ的化学计量比称取原料Li2CO3 3.390g、MgO 2.418g和Sb2O3 4.192g,将原料混合物与锆球、无水乙醇按质量比为 1∶2∶2装入尼龙球磨罐中,充分混合球磨8小时,90℃干燥5小时。其他步骤与实施例1相同,制备成微波介质陶瓷。
实施例3
在实施例1的步骤5中,将圆柱形生坯在1200℃烧结5小时,其他步骤与实施例1相同,制备成微波介质陶瓷。
实施例4
在实施例1的步骤5中,将圆柱形生坯在1225℃烧结5小时,其他步骤与实施例1相同,制备成微波介质陶瓷。
实施例5
在实施例1的步骤3中,将圆柱形生坯在1275℃烧结5小时,其他步骤与实施例1相同,制备成微波介质陶瓷。
对比例1
按Li3Mg2SbO6的化学计量比称取Li2CO3 3.317g、MgO 2.365g、Sb2O3 4.318g,装入尼龙球磨罐中,加入20g锆球、20g无水乙醇,用行星球磨机充分混合球磨8 小时,转速为360转/分钟,球磨完后置于烘箱内90℃干燥5小时,然后装入刚玉坩埚中950℃预烧4小时,制备成Li3Mg2SbO6预烧粉。将Li3Mg2SbO6预烧粉进行二次球磨8小时,再烘干,加入0.5g质量分数为5%的聚乙烯醇水溶液进行造粒,过120目筛,用粉末压片机在4MPa压力下压制成直径为10mm、厚度为5mm 的圆柱形生坯,将圆柱形生坯在1200℃烧结5小时,制备成微波介质陶瓷。
对比例2
按Li3SbO4的化学计量比称取Li2CO3 4.345g、Sb2O3 5.655g,装入尼龙球磨罐中,加入20g锆球、20g无水乙醇,用行星球磨机充分混合球磨8小时,转速为360转/ 分钟,球磨完后置于烘箱内90℃干燥5小时,然后装入刚玉坩埚中900℃预烧4小时,制备成Li3SbO4预烧粉。然后按Li3Mg2SbO6的化学计量比称取Li2SbO4预烧粉 7.192g、Sb2O32.808g装入尼龙球磨罐中进行二次球磨8小时,再烘干,加入0.5g 质量分数为5%的聚乙烯醇水溶液进行造粒,过120目筛,用粉末压片机在4MPa 压力下压制成直径为10mm、厚度为5mm的圆柱形生坯,将圆柱形生坯在1300℃烧结5小时,制备成微波介质陶瓷。
对比例3
在实施例1的步骤1中,按照Li3Mg2Sb0.875O6-δ的化学计量比称取原料Li2CO33.506g、MgO 2.500g和Sb2O33.994g,将原料混合物与锆球、无水乙醇按质量比为 1∶2∶2装入尼龙球磨罐中,充分混合球磨8小时,90℃干燥5小时。其他步骤与实施例1相同,制备成微波介质陶瓷。
发明人采用RagukuD/Max2550(Japan)型X射线衍射仪对实施例1~5制备的Sb 位非化学计量比Li3Mg2Sb1-xO6-δ微波介质陶瓷进行表征,结果见图1。由图1可见,所制备的Li3Mg2Sb1-xO6-δ微波介质陶瓷由岩盐结构的纯相Li3Mg2SbO6所组成,未检测到明显其它相。
发明人采用闭腔谐振法,用ZVB20矢量网络分析仪(由德国罗德&施瓦茨公司生产)对实施例1~5以及对比例1~3制备的微波介质陶瓷进行微波介电性能测试,样品的谐振频率温度系数在20~80℃温度范围内测试,TE01δ谐振模的频率在 10.0~12.0GHz范围内,测试结果与公开号为CN 105693241A、发明名称为“温度稳定型锑酸镁锂基微波介质复合陶瓷及其制备方法”中实施例1制备的 0.9Li3Mg2SbO6-0.1Ba3(VO4)2复合陶瓷,现有文献报道的Li3Zn2SbO6(Microwave Dielectric Properties of the Lithium Containing Compoundswith Rock Salt Structure, Ferroelectrics,387:123-129,2009)、Li3Mg2Nb0.94Sb0.06O6(Effect of Sb5+ion substitution for Nb5+on crystal structure and microwavedielectric properties for Li3Mg2NbO6 ceramics, Journal of Alloys andCompounds,766:498-505,2018)陶瓷材料的微波介电性能进行比较,结果见表1。
表1不同陶瓷材料的微波介电性能对比
Figure BDA0002236558640000041
Figure BDA0002236558640000051
注:表中-表示由于样品破裂无法准确计算其εr
试验结果显示:对比例1制备的陶瓷不仅烧结后发生破裂,无法获得圆柱形陶瓷(如图2所示),且具有较大的负谐振频率温度系数,对比例2制备的陶瓷不仅烧结温度高,而且制备工艺复杂(需要先制备出Li3SbO4前躯体),本发明实施例1~ 5通过在Li3Mg2SbO6陶瓷中引入适量的Sb位晶格缺陷,不仅可改善其烧结特性(抑制Li3Mg2SbO6陶瓷开裂(见图3)、降低其烧结温度),而且可改善其微波介电性能(Q×f最高提升约170%),但是对比例3中引入过多Sb位晶格缺陷,导致陶瓷的 Q×f值明显降低。同时,与文献报道的Li3Zn2SbO6、Li3Mg2Nb0.94Sb0.06O6陶瓷相比,本发明实施例1~5制备微波介质陶瓷具有较好温度稳定性;与 0.9Li3Mg2SbO6-0.1Ba3(VO4)2复合陶瓷相比,本发明陶瓷具有更低的介电损耗。

Claims (4)

1.一种改善Li3Mg2SbO6陶瓷烧结特性和微波介电性能的方法,其特征在于:
(1)按照Li3Mg2Sb1-xO6-δ的化学计量比,式中0.05≤x≤0.10,将原料Li2CO3、MgO、Sb2O3加入球磨罐中,以锆球为磨球、无水乙醇为球磨介质,充分混合球磨6~10小时,80~100℃干燥;
(2)将步骤(1)干燥后的混合物在850~900℃预烧2~6小时,得到预烧粉;
(3)将步骤(2)得到的预烧粉加入球磨罐中,以锆球为磨球、无水乙醇为球磨介质,充分混合球磨6~10小时,80~100℃干燥;
(4)向步骤(3)干燥后的预烧粉中加入质量分数为5%的聚乙烯醇水溶液进行造粒,过80~120目筛,用粉末压片机压制成圆柱形生坯;
(5)将圆柱形生坯在1200~1275℃烧结1~10小时。
2.根据权利要求1所述改善Li3Mg2SbO6陶瓷烧结特性和微波介电性能的方法,其特征在于:步骤(1),0.09≤x≤0.10。
3.根据权利要求1所述的改善Li3Mg2SbO6陶瓷烧结特性和微波介电性能的方法,其特征在于:步骤(2)中,将步骤(1)干燥后的混合物在900℃预烧4小时。
4.根据权利要求1所述的改善Li3Mg2SbO6陶瓷烧结特性和微波介电性能的方法,其特征在于:步骤(5)中,将圆柱形生坯在1250℃烧结5小时。
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