Waterproof monolithic capacitor prevents ion migration

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 ionised 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-repellant treatment film so that moisture forms into scattered droplets, rather than larger ones. 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 ECUs, air conditioner ECUs, meter ECUs and engine ECUs.

Sample shipments have already begun and the capacitor is scheduled to enter mass production within the year.