ADVANCED TESTING PROCEDURES FOR HIGH PERFORMANCES COATINGS

摘要

For industrial applications, it is often required to use protective organic coatings with very high corrosion protection performances and durability. In order to develop organic coatings products with good characteristics it is critical to use testing procedures able to produce quickly reliable results. For this purpose a lot of different testing methods are used in the industrial practice and in the research laboratories, but often the potentials and the limits of the different testing methods are not completely understood. In the first part of this work some organic coatings from automotive production were characterised by using an integrated approach including electrochemical techniques (impedance spectroscopy EIS), calorimetric (differential scanning calorimetry DSC), mechanical (dynamo-mechanical thermal analysis) and infrared spectroscopy (Fourier transfer infrared spectroscopy FTIR). The comparison of the results obtained with different techniques allows, not only a higher precision in the natural or artificial degradation evaluation which is very difficult to obtain by using just traditional technique, but also a better data interpretation and therefore the possibility to understand the different degradation mechanisms. In the second part of the paper are discussed some preliminary results concerning the comparison of salt spray exposure and EIS measurements. The statistical analysis of the results showed that the degradation mechanism in the two cases is completely different and therefore different is also the information which it is possible to obtain with the two testing approaches.