  We present a new approach for real-time monitoring of chemical corrosion
based on the radio-frequency (RF) impedance technology and soft ferromagnetic
ribbons. The impedance (Z) of a commercial magnetic ribbon was measured in real
time for 5 mul of drop-casted HNO3 of various concentrations. Variations in the
concentration of the drop-casted acid were assessed by considering the
difference in Z with and without the acid treatment. We found a large and
linear increase in deltaZ and a large linear decrease in measurement time with
the acid concentration, which are ideal for developing disposable chemical
sensors for strength estimation of corrosive chemicals and for monitoring of a
time-dependent chemical corrosion process. Since the ribbon used is
commercially available at low cost and the measurement system is quick and low
power consuming, the proposed sensor can be used as an easy, quick, and
low-cost chemical probe in industries and environmental hazard management
purposes.
