H_3BO_3或SiO_2掺杂对CTLA陶瓷微波介电性能的影响

Influence of H_3BO_3 or SiO_2 Additive on the Microwave Dielectric Properties of CTLA Ceramics

研究了H3BO3或SiO2掺杂(质量分数为0.02%～2.00%)对0.61CaTiO3-0.39LaAlO3陶瓷的烧结温度、晶体结构及微波介电性能的影响。结果表明,微量的H3BO3或SiO2掺杂可使0.61CaTiO3-0.39LaAlO3陶瓷的烧结温度从1 380℃降至1 340℃,2.00%以内的H3BO3或SiO2掺杂不会改变陶瓷的物相组成。在H3BO3掺杂质量分数为2.00%时,样品的微观形貌发生了很大的改变,烧成的陶瓷稀疏多孔,密度急剧下降。研究表明,H3BO3或SiO2掺杂对0.61CaTiO3-0.39LaAlO3陶瓷的介电常数εr及谐振频率温度系数τf没有很大的影响,但降低了陶瓷的品质因数Q。当质量分数为0.02%时,H3BO3或SiO2掺杂后的0.61CaTiO3-0.39LaAlO3陶瓷的微波介电性能最佳:H3BO3掺杂的陶瓷样品的εr=41.65,品质因数与频率之积Q×f=48 565GHz,τf≈-1μ℃-1;SiO2掺杂的陶瓷样品的εr=41.48,Q×f=39 491GHz,τf≈-1μ℃-1。

The influence of H3BO3 or SiO2 additive（0.02%-2.00%） on the sintering temperatures,crystal structures and microwave dielectric properties of 0.61CaTiO3-0.39LaAlO3 ceramics were investigated.The results showed that the sintering temperature of 0.61CaTiO3-0.39LaAlO3 ceramics could be lowered from 1 380 ℃ to 1 340 ℃ by doping low-level addition of H3BO3 or SiO2 and no phase change was observed when the addition was less than 2.00%.The microstructure of the specimen with 2.00% addition of H3BO3 was changed greatly and the density decreased rapidly because many pores were appeared.The dielectric constant（εr） and the temperature coefficient of resonant frequency（τf） of 0.61CaTiO3-0.39LaAlO3 ceramics were not significantly affected by doping H3BO3 or SiO2,but the quality factors（Q×f） dropped.The excellent microwave dielectric properties were obtained for 0.61CaTiO3-0.39LaAlO3 ceramics with 0.02% addition of H3BO3 or SiO2.The features of the ceramic specimen with H3BO3 addition are that εr is equal to 41.65,Q×f is equal to 48 565 GHz,and τf is equal to-1 μ℃-1 and εr =41.48,Q×f≈39 491 GHz,and τf =-1 μ℃-1 for SiO2 doped ceramic sample.