Li2O-B2O3-SiO2玻璃相对BaAl2Si2O8结构及微波介电性能的影响

采用固相工艺制备BaAl₂Si₂O₈-xwt%Li₂O-B₂O₃-SiO₂(x=0, 0.1, 0.3, 0.5, 1.0, 2.0)陶瓷。探究不同含量的Li₂O-B₂O₃-SiO₂(LBS)玻璃相对BaAl₂Si₂O₈(BAS)陶瓷的烧结温度、结构及微波介电性能的影响。结果表明: LBS玻璃相可明显降低BAS陶瓷的烧结温度, 并促进BAS陶瓷晶粒长大和晶体结构由六方相转变为单斜相。当x=0.1时, 六方相即可全部转变为单斜相, 在0.1≤x≤2.0范围内, BAS陶瓷晶体结构均为单斜相。添加0.3wt%的LBS玻璃相可促进BAS样品密度、介电常数和品质因数增大, 谐振频率温度系数绝对值减小。在x=0.3, 烧结温度为1275 ℃时, 可获得具有较好品质因数的单斜钡长石, 其介电性能: ε_r=6.74, Q×f=34570 GHz, τ_f= -15.97×10 ^-6/℃。

Structure and Microwave Dielectric Property of BaAl2Si2O8 with Li2O-B2O3-SiO2 Glass Addition

The BaAl₂Si₂O₈-xwt%Li₂O-B₂O₃-SiO₂ (x=0, 0.1, 0.3, 0.5, 1.0, 2.0) ceramics with small amount of Li₂O-B₂O₃-SiO₂ (LBS) glass addition were prepared by solid state sintering. The sintering temperature, structure and microwave dielectric properties of BaAl₂Si₂O₈ (BAS) ceramics with xwt%LBS glass addition were investigated. The results show that the LBS glass can greatly reduce the sintering temperature, promote the growth of grain and the transformation of hexacelsian-to-celsian of BAS ceramics. As x=0.1, all the hexacelsian were transformed into celsian, and the second phase was not observed as x≤2.0. The 0.3wt%LBS glass can promote the density, dielectric constant and Q × f value increase, and the absolute value of τ_f decrease. Especially, the BAS ceramics with the 0.3wt%LBS glass addition sintered at 1275 ℃ shows a good Q × f of 34570 GHz, and the dielectric properties are ε_r = 6.74 and τ_f = -15.97 × 10 ^-6/℃.