Dielectric ceramic with stable relative permittivity and low loss from-60 to 300 °C: A potential high temperature capacitor material

A new dielectric is described that meets the industry-standard lower limiting temperature of stable performance, -55 degrees C whilst extending the upper limit to 300 degrees C, with low dielectric loss, as required for the growing high-temperature electronics sector. The combined substitution of Sr and Bi ions on A sites, and Mg and Zr ions on B sites of the ABO(3) perovskite solid solution (1 - x)Ba0.6Sr0.4Zr0.2Ti0.8O3-xBi(Mg0.5Ti0.5)O-3 flattens the epsilon(r)-T response. At composition x=0.2 the epsilon(rmax) temperature, and the associated tan 8 dispersion peak, are each displaced to low temperatures such that a very favourable combination of low dielectric loss, tan delta < 0.015, from -60 to 310 degrees C and stable epsilon(r), similar to 500 +/- 15% from -70 to 300 degrees C (1 kHz data) are demonstrated. Hence the x=0.2 material achieves stable epsilon(r) and low loss over the technologically important target temperature range, -55 to 300 degrees C. (C) 2016 Elsevier Ltd. All rights reserved.