# Electrical Property Measurement on Antistatic Coating During Aging Process
## 3 Results and Discussion
### Capacitance and Loss Factor Measurement  
The second set of measurements focused on paint capacitance and loss factor measurements depending on the frequency. The capacitance and loss factors measured before and after aging show that the electrical parameters of the painting changed. The measurement methods used in our experiments are usually applied in dielectric spectroscopy for electric parameter measurements, in general, and they can be applied for the measurement of anistatic material electric parameters. They are AC (alternating current) methods, and they were made by the IDAX-300 insulation diagnostic analyzer (Figure 3) in the following frequency ranges:  
* 10,000 Hz, 9000 Hz-1000 Hz;
* 900 Hz, 800 Hz-100 Hz;
* 9 Hz, 80 Hz-10 Hz;
* 9 \(\times\) 10\({}^{-1}\) Hz, 8 \(\times\) 10\({}^{-1}\) Hz-1 \(\times\) 10\({}^{-1}\) Hz;
* 9 \(\times\) 10\({}^{-2}\) Hz, 8 \(\times\) 10\({}^{-2}\) Hz-1 \(\times\) 10\({}^{-2}\) Hz;
* 9 \(\times\) 10\({}^{-3}\) Hz, 7 \(\times\) 10\({}^{-3}\) Hz, 5 \(\times\) 10\({}^{-3}\) Hz, 3 \(\times\) 10\({}^{-3}\) Hz, 2 \(\times\) 10\({}^{-3}\) Hz, 1 \(\times\) 10\({}^{-3}\) Hz.  
According to the simplified model of our samples shown in Figure 4 and Equations (3) and (4), the capacitance and loss factor influence the coating's capability to eliminate the charge because the resistance of the coating is inversely proportional to the capacitance and loss factor measured.  
The \(I_{Cp}\) current and the \(I_{Rp}\) current can be calculated as in Equations (1) and (2). Then, we can substitute these currents in Equation (3), indicating the calculation of the loss factor, and Equation (4) calculates the corresponding resistivity.  
\[I_{C_{p}}=\frac{U}{X_{C}} \tag{1}\]  
Figure 4: Simplified model of samples.  
Figure 3: Measurement setup by IDAX-300 insulation diagnostic analyzer.  
\[I_{R_{P}}=\frac{U}{R} \tag{2}\]  
\[\tan\delta=\frac{I_{R_{P}}}{I_{C_{P}}}=\frac{\frac{U}{R}}{\frac{U}{\mathcal{X}_{C }}}=\frac{X_{C}}{R}=\frac{1}{R\cdot\omega\cdot C} \tag{3}\]  
\[R=\frac{1}{\tan\delta\cdot\omega\cdot C} \tag{4}\]  
The measurements were made at a constant voltage of 10 V on a dielectric pad. These measurements are very time-consuming, as at \(f\) = 1 mHz, the measurement period lasts 1000 s. In our case, the measurement took approximately 58 min.  
The capacitance between electrodes (without sample) during the AC measurement methods was compensated by the measuring device itself (it has a built-in compensation), so this capacitance was not measured in our experiments. The capacitance values of the samples on both pad materials were in the range of hundreds of pF. The highest capacitance was observed on BISIL paint; on the other hand, CaTiO\({}_{3}\) had, in both cases, the lowest capacitance. TiO\({}_{2}\)/PANI and PANI conductive polymer paints were exceptions, which had a capacitance value range of tens of pF at mHz frequency values on steel pad.  
The measurement of the loss factor quantifies the paint's conductivity. We found that the non-conductive paints on glass sheets have greater values of the loss factor. The influence of conductive polymers can be observed in the case of steel pads. In these cases, for TiO\({}_{2}\)/PANI paint and at frequencies near 1/100 Hz, the loss factor had a value of \(tg\)\(\delta\approx\) 52. For PANI paint at mHz range frequencies, the \(tg\)\(\delta\approx\) 11, and for CaTiO\({}_{3}\)/PANI at low frequencies, the loss factor was \(tg\)\(\delta\approx\) 1.7. In addition, the BISIL paint had a higher loss factor value: \(tg\)\(\delta\approx\) 1.4 at lower frequencies. In comparison with other cases, these loss factor values can be considered as high values, as normally they are in the range of 1/10 units.