With the rapid advancement of the electronics industry, there is an urgent demand for the development of high-voltage ceramic capacitors characterized by high breakdown voltage, low loss, compact size, and high reliability. Over the past two decades, high-voltage ceramic capacitors successfully developed both domestically and abroad have found widespread application in power systems, laser power supplies, video recorders, color televisions, electron microscopes, photocopiers, office automation equipment, aerospace, missile systems, and marine navigation, among other fields.
The ceramic materials used in high-voltage ceramic capacitors primarily fall into two major categories: barium titanate-based and strontium titanate-based materials.
Barium titanate-based ceramic materials offer the advantages of a high dielectric constant and superior AC voltage withstand characteristics.
Strontium titanate crystals possess a Curie temperature of -250°C; at room temperature, they exhibit a cubic perovskite crystal structure and function as paraelectrics, meaning they do not exhibit spontaneous polarization. Under high-voltage conditions, strontium titanate-based ceramic materials demonstrate minimal variation in dielectric constant, as well as low dielectric loss (tgδ) and minimal capacitance drift. These advantages make them highly suitable for use as the dielectric medium in high-voltage capacitors.