复合烧结助剂对CSLST微波介质陶瓷的性能影响

Effects of Composite Sintering Additives on Properties of CSLST Microwave Dielectric Ceramics

研究了复合添加12.5wt%Li2CO3-B2O3-CuO(LBC)玻璃和不同含量(0～4.0wt%)Bi2O3对(Ca0.9375Sr0.0625)0.3(Li0.5Sm0.5)0.7TiO3(CSLST)微波介质陶瓷烧结特性、相组成和介电性能的影响,分析了CSLST陶瓷与银的共烧行为。结果表明:复合添加LBC玻璃和Bi2O3能有效降低CSLST陶瓷烧结温度至875℃,XRD分析结果显示添加0～1.0wt%Bi2O3有Cu3Ti3O和CaCu3Ti4O12新相产生,当Bi2O3的添加量大于2.0wt%,杂相消失。随着Bi2O3添加量的增加,陶瓷的频率温度系数τf向负方向偏移。复合添加12.5wt%LBC玻璃和2.0wt%Bi2O3的CSLST陶瓷,在875℃保温5 h烧结后,具有优良的微波介电性能:εr=78.9,Q×f=1852 GHz,τf=3×10-6/℃。该材料与银共烧界面结合状况良好,无明显扩散,适合作为LTCC的材料。

The effect of the compound of 12.5wt% Li2CO3-B2O3-CuO（LBC） glass and different content（0-4.0wt%）Bi2O3 addition on the sintering properties,phase structures and dielectric properties of（Ca0.9375Sr0.0625）0.3（Li0.5Sm0.5）0.7TiO3（CSLST） microwave dielectric ceramics were investigated.The results indicated that the compound can effectively decrease the sintering temperature of CSLST ceramic to 875 ℃.The secondary phases of Cu3Ti3O and CaCu3Ti4O12 were found when the content of Bi2O3 was 0-1.0wt% by XRD analysis.When the content was more than 2.0wt%,the secondary phases disappear.As the Bi2O3 content increasing,the temperature coefficient of the resonance frequency（τf） decreases monotonously.The sample of CSLST with 12.5wt% LBC and 2.0wt% Bi2O3 sintered at 875 ℃ for 5 h exhibited the best microwave dielectric properties： εr=78.9,Q×f=1852 GHz,τf =3×10-6/℃.The co-firing interface between microwave ceramics and Ag has good cohesion and there is no obvious diffusion at the interface,This material is suitable for LTCC.