New passive ceramic sensor for corrosion detection

We present in this paper a new passive ceramic corrosion sensor which can be integrated into a structure submitted to a corrosive environment. The corrosion detection mechanism is based on the modification of a resonator frequency as a function of the corrosion level. An alumina substrate is covered with a metal enclosure that is protected against corrosion apart from the middle of the top face. This latter, patterned as a grid, is made of a metal sensitive to corrosion. The cracks caused by the corrosion in the grid introduce a capacitive effect and cause a frequency shift of the resonance mode (f_r), and a degradation of unloaded quality factor (Q₀) as a function of the corrosion level.