Properties of beryllium-barium titanate dielectrics

Abstract

The results on barium-strontium titanates are given for heat treatments, absorption, shrinkage, thermal expansion, dielectric constant (K) at -600 to 850 C, and also for Q, the reciprocal 01 the power factor, at 250 C for frequencies of 50 to 20,000 kc/s. A few measure- ments of K and Q were made at 3,000 me/s. Specimens matured (absorption less than 0.1 percent) at 1,2500 to 1,4300 C. K values ranged from 34, for BaO:4Ti02 , to several thousand for specimens with compositions on the BaTi03 -SrTiOa join. Specimens having the com- position BaO:5Ti02 were unique in that their temperature coefficient of K was practically zero. Q values ranged from 50 to 100 for test pieces containing over 40 percent of BaO, and from 400 to 10,000 for those with less than 40 percent of BaO. K values did not change appreciably with frequency. Linear thermal expansions between 250 and 7000 C ranged from 0.6 to 0.84 percent. Many of these specimens could be used in radio equipment. I.