Lead Perovskite Relaxor-Based Low-Loss Ceramic Dielectric for High-Voltage Ceramic Capacitors

Abstract

A low-loss ceramic dielectric with a less than 0.1% dissipation factor at 100 kHz, based on a modified lead zinc niobate relaxor, has been fabricated by shifting the ferroelectric transition temperature (Tc) to below -55°C. This dielectric has a high dielectric constant (K), ranging from 250 to 2000. The temperature coefficient of capacitance (TCC) locates at the middle area between values for temperature compensation dielectric and values for high-K dielectric. Even at 150°C, high insulation resistance, more than 5×1013 Ωcm, was also retained. Moreover, a typical composition with K=530 revealed that the dielectric has a high breakdown voltage of 95 kV per 10 mm of thickness and a TCC value of -2900 ppm/°C. Accordingly, this dielectric has proven useful for high-voltage ceramic capacitors.