Ion migration may occur when voltage is applied to a capacitor where moisture is present between the electrodes. This may result in the anode metal becoming ionized and changing to a cathode. Then, when gaining electrons as a cathode, the metal may undergo the electrochemical phenomenon of deposition and growth that can eventually result in a short-circuit. This is particularly prone to occur when the capacitor is moistened by condensation.
To address this issue Murata has developed a water-repellent monolithic ceramic capacitor. The monolithic capacitor is treated with a water-repellent film so that moisture forms into scattered, rather than larger, droplets. These droplets are suppressed to a size that is not big enough to span the gap between the external electrodes, and this prevents ion migration.
This capacitor has applications particularly in navigation systems, body control electronic control units (ECUs), air conditioner ECUs, meter ECUs and engine ECUs. The capacitor is scheduled to enter mass production within the year.