What is capacitance aging of ceramic capacitors?
Capacitance of high dielectric type ceramic capacitors gradually decreases over time. This phenomenon is called aging. Aging occurs because substances constructing ceramic capacitors gradually change their structure to be more stable electrically. This is a common phenomenon generally observed in ceramic capacitors. The reduced capacitance returns to the original value through thermal treatment.
This is not the case for temperature compensating type products such as Multilayer Ceramic Capacitors(Temperature compensating type) and Multilayer Ceramic Capacitors for High Frequency Applications (1GHz+) because used materials are different from high dielectric type.