The dielectric and mechanical strength in barium titanate ceramics were measured as a function of grain size at 140℃ and 25℃, respectively, where grain size was controlled by sintering time at 1335℃. Both the dielectric and mechanical strength decrease with grain size. In the range of grain size below about 20㎛, dielectric strength at 140℃ is higher than that at 25℃, and vice versa above 20㎛. The mechanical strength is higher at 140℃ than that at 25℃. Though some analogy between dielectric and mechanical strength appears, the mechanism of dielectric breakdown in barium titanate ceramics seems to be different from that of mechanical fracture.
