The Electrical Degradation of a Low-Loss Capacitor Prepared by Sintering a Glass Powder

The electrical degradation of capacitors prepared by sintering glass powder was investigated in connection with crystallization in the glass and sinterability of the glass powder. Crystallization in glass is responsible for a decrease in volume resistivity and an increase in dissipation factor after a life test under voltage stress at high temperature. These degradations are attributed to an increase in concentration of both mobile alkali ions in the glass matrix and of silver ions from the electrode diffused into the glass matrix, owing to the crystallization. The temperature of life test has more effect on the degradation than the applied voltage stress, and is considered to be a determining factor in the life test of a crystallized glass. While the degradation of a capacitor is also influenced by crystallization, it is more strongly influenced by the sinterability of the glass powder from which it is made. Poor sinterability is responsible for the existence of glass particle boundaries, which results in degradation.