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

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

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:εr=6.74, Q×f=34570 GHz,τf=–15.97×10^–6/℃。

The BaAl2Si2O8-xwt%Li2 O-B2 O3-SiO2(x=0, 0.1, 0.3, 0.5, 1.0, 2.0) ceramics with small amount of Li2 O-B2 O3-SiO2(LBS) glass addition were prepared by solid state sintering. The sintering temperature, structure and microwave dielectric properties of BaAl2 Si2 O8(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 0.3 wt%LBS glass can promote the density, dielectric constant and Q × f value increase, and the absolute value of τf decrease. Especially, the BAS ceramics with the 0.3 wt%LBS glass addition sintered at 1275 ℃ shows a good Q × f of 34570 GHz, and the dielectric properties are εr = 6.74 and τf =–15.97 × 10^–6/℃.