成型工艺对CBS系微晶玻璃结构与性能的影响

Effects of molding process on structure and properties of CaO-B_2O_3-SiO_2 glass ceramics

采用干压成型和流延成型工艺制备CaO-B2O3-SiO2(CBS)系生坯。考察成型工艺对CBS微晶玻璃的烧结性能与介电性能的影响;用X线衍射仪(XRD)、扫描电镜(SEM)对试样进行表征。结果表明:与干压成型相比,流延成型体系中没有出现新的晶相,流延成型试样的体积密度和收缩率有所增加,有利于介电常数提高和介质损耗的降低;850℃烧结的流延成型试样,体积密度达到2.58 g/cm3,X、Y轴收缩率均为15.35%,10 GHz时介电常数和介电损耗分别为6.45和8×10-4,300℃的热膨胀系数为12.02×10-6K-1,抗弯强度为161.18 MPa,热导率为1.9 W/(m.K)。CBS微晶玻璃与Ag电极高温烧结后金属Ag布线断裂。金属Ag电极浆料与生料带共烧时,Ag+能够沿着基片表面不致密部分扩散,而相对致密的晶相,能够在一定程度上阻碍Ag+扩散。

CaO-B2 O3-SiO2（CBS） glass ceramics were prepared by dry-process and tape casting.The effects of dry-process and tape casting on sintering and dielectric properties were investigated.The CBS glass ceramics were characterized by X-ray diffraction（XRD） and scanning electron microscope（SEM）.Results indicated that compared with the dry-process,the tape-casting sintering samples had high density,large X and Y shrinking rate,small Z shrinking rate,high dielectric constant,and low dielectric loss.By tape-casting,the CBS glass ceramics achieved excellent properties at 850 ℃,such as bulk density of 2.58 g/cm3,X and Y shrinking rate of 15.35%,dielectric constant of 6.45 and dielectric loss of 8×10-4 at 10 GHz,linear thermal expansion coefficient（CTE） of 12.02×10-6 K-1（300 ℃）,bending strength of 161.18 MPa,and thermal conductivity of 1.9 W/（m·K）.Ag ions were diffused through undense regions containing glass phases,and the crystalline phases behaved as a barrier for the Ag＋ diffusion.