The results show a progressive loss of the upper vibrational modes of the string and a decreasing duration time of the signal with
the progress in the process of controlled corrosion.
Electrical resistivity and EIS measurements (“dry” measurements) on the strings did not show a notable increase of electrical resistivity after the three days of corrosion attack. Measurements of weight loss did not also show a significant weight decrease of the
strings due to the corrosion process throughout the first three days under corrosion. In contrast, a drastic decrease (one order of magnitude) was observed for Rp measurements in synthetic human sweat solution. Rp measurements in synthetic human sweat provided
a suitable method to control the sound characteristics of strings during corrosion processes. An appropriate correlation was obtained
between polarization resistance Rp and sound amplitude (FFT) measurements.
In conclusion, electrochemical methods could be applied to evaluate changes in acoustic behavior of strings of musical instruments
by means of a controlled corrosion process.
In fact, at this time, our research team is using the working method detailed in this manuscript to evaluate the effectiveness of various methods to prevent corrosion on the strings of musical instruments.
Two hypotheses were established: Impressed current protection and sacrificial anode protection could diminish the corrosion in
guitar strings immersed in artificial human sweat. Preliminary results showed a lower level of corrosion using impressed current cathodic protection.