钨酸盐类陶瓷微波介电性能

MICROWAVE DIELECTRIC PROPERTIES OF TUNGSTATE CERAMICS

研究了钨酸盐AWO4(A=Ca,Sr,Ba,Zn,Mg)系列陶瓷材料的微结构、烧结性能以及微波介电性能。AWO4具有黑钨矿和白钨矿两种结构。无论白钨矿还是黑钨矿,其相对介电常数rε和介电品质因素Q×f值都随着阳离子A2+半径的增大而减小,谐振频率温度系数τf绝对值增大。白钨矿结构的CaWO4具有较好的微波性能:rε=10.0,Q×f=50.842 THz,τf=-50×10-6/℃。

Tungstate AWO4 （A=Ca, Sr, Ba, Zn, Mg） ceramics were prepared by a solid state reaction process. The sinterability, microstructure and microwave dielectric properties were investigated by X-ray diffraction （XRD） and Hewlett -Packard network analyzer. Both of the relative dielectric constant （εr） and the quality factor （Q）×f） decrease with the increasing of A^2＋ radius whatever for scheelites or wolframites, and the absolute value of temperature coefficient of resonant frequency （τf） increases with the ionic radius of A^2＋. Among them, CaWO4 with scheelite structure has good microwave dielectric properties εr=10.0,Q×f=50.842THz,τf=50×10^-6/℃.