多元体系低温烧结微波介质陶瓷的设计、制备及性能优化

发布时间：2018-06-24 00:42

  本文选题：微波介质陶瓷 + 低温烧结　； 参考：《桂林理工大学》2016年硕士论文

【摘要】：随着无线通讯设备不断向小尺寸、集成化方向发展,微波介质陶瓷材料不仅需要适当的介电常数(εr),高的品质因素(Q×f)以及较低的谐振频率温度系数(τf),同时也需要有较低的烧结温度,以便与低熔点的电极共烧,满足LTCC(低温共烧陶瓷)技术的要求。本文通过传统的固相反应法制备了5Mg_O-3Li2_O-4W_O_3、Li_4xMg_(3(1-x))Al_(6(1-x))Ti_5O_(12)、Li_4Ti_5O_(12)等新型低温烧结微波介质陶瓷,系统研究了LiZnNbO_4陶瓷的低温化烧结、工艺优化、烧结特性及性能调节,并对上述陶瓷与Ag电极的低温共烧进行了初步探讨。(1)采用传统的固相反应法制备了5MgO-3Li_2O-4WO_3新型低烧微波介质陶瓷,通过XRD、SEM以及微波网络分析仪研究了该陶瓷的相结构、原子占位、烧结性能及微波介电性能。5Mg O-3Li_2O-4WO_3陶瓷不仅具有低的烧结温度(≤840 oC),而且还具有低介电常数~10.3,高品质因素~20,537 GHz(在~11GHz频率下)。该材料能与Ag共烧兼容,表明其可作为LTCC器件的备选材料。(2)对比研究了不同原材料处理方式对Li Zn Nb O4陶瓷相转变、显微结构、烧结特性及微波介电性能的影响,恰当的原材料处理使得Li Zn Nb O4陶瓷在一个较低的温度区间(950~1070 oC)获得高的品质因数(Q×f),改善了Li Zn Nb O4陶瓷的烧结特性,并降低其烧结温度。加入一定量的Ca Ti O_3来调节Li Zn Nb O_4陶瓷的τf,1070 oC烧结的0.9Li Zn Nb O_（4-0.1）Ca Ti O_3陶瓷具有优异的微波介电性能:εr=22.9,Q×f=10,583 GHz(谐振频率f~7.4 GHz),τf=-27.5 ppm/oC。(3)研究了Li_4xMg_(3(1-x))Al_(6(1-x))Ti_(5x) O_(12)(0.2≤x≤0.8)微波介质陶瓷体系的相结构、微观形貌及微波介电性能。Li_(4x)Mg_(3(1-x))Al_(6(1-x))Ti_(5x) O_(12)(0.2≤x≤0.8)陶瓷表现出良好的综合性能:εr=11.5~26.5,Q×f=7,102~30,191 GHz,τf=-55.4~+5.7 ppm/°C,烧结温度可以从1280 oC降低至925°C。值得注意的是,Li_(4x)Mg_(3(1-x))Al_(6(1-x))Ti_(5x) O_(12)(x=0.6)陶瓷在1075°C时烧结显示出中等的εr~18.8,高Q×f~12,429 GHz(谐振频率f~8 GHz),近零的τf~-6.0 ppm/°C。(4)通过传统的固相法制备了新型Li4Ti5O12低烧微波介质陶瓷,并对其相结构、烧结特性、微观晶粒形貌以及微波介电性能进行了较为系统的研究。XRD分析表明其具有立方尖晶石结构(JCPDS file No.00-049-0207)。该陶瓷在925°C烧结时,获得最佳的微波介电性能:中等介电常数~31.5,高品质因数(Q×f)~29,530 GHz(谐振频率f~7GHz),以及小的谐振频率温度系数(τf)~-15.0 ppm/°C。当烧结温度上升到1025°C以上,析出的Ti O2相使得混和相的谐振频率温度系数调节近零。
[Abstract]:With the development of wireless communication equipment to the direction of small size and integration, Microwave dielectric ceramic materials need not only proper dielectric constant (蔚 r),) high quality factor (Q 脳 f) and lower resonant frequency temperature coefficient (蟿 f), but also lower sintering temperature to co-burn with low melting point electrode. Meet the requirements of LTCC (low temperature co-fired ceramics) technology. In this paper, a new type of low-temperature sintering microwave dielectric ceramics, such as 5MgO-3Li2SnO-4WSP, Li4xMg3 (1-x) Al6 (1-x) Ti5O12 / Li4Ti5O12, has been prepared by traditional solid state reaction method. The low temperature sintering, process optimization, sintering characteristics and performance adjustment of LiZnNbO4 ceramics have been systematically studied. The low temperature co-firing of the above ceramics with Ag electrode was discussed. (1) 5MgO-3Li2O-4WO3 microwave dielectric ceramics were prepared by conventional solid state reaction. The phase structure and atomic occupation of the ceramics were studied by XRDX SEM and microwave network analyzer. Sintered and microwave dielectric properties. 5mg O-3Li2O-4WOS3 ceramics not only have low sintering temperature (鈮，

本文编号：2059185