| Abstract: | Using a commercial capacitance bridge the capacitance and dielectric properties of pigmented paint films were measured with a view to the possibility of forecasting the corrosion protection properties of such coatings. According to the results obtained with 8 red lead and 4 iron oxide pigmented primers on steel in sodium chloride and sodium perchlorate solutions the measured values of the capacitance and of the dissipation factor enable really pure and really good primers to be distinguished after only 3 days. However, it is not possible to grade high quality primers of different generic types from dielectric data, irrespective of the duration of exposure (up to 12 months). This finding is ascribed to the differences in the duration of the initial wetting and swelling period. |
