The present disclosure relates to electrical machines. The teachings thereof may be embodied in a corona shielding system, especially for an electrical machine, e.g., a high-voltage machine, such as a generator for generation of electrical energy, an electric motor, or another piece of electrical equipment having a relatively high rated voltage, e.g., a transformer or a bushing or a cable. A corona shielding system may include: a polymeric matrix; and filler particles comprising mica surrounded by a layer of at least one ceramic metal oxide. The filler particles may be distributed throughout the polymeric matrix.