Technicians were tasked with measuring the performance of anti-corrosion coatings. These coatings were produced with natural materials such as egg shells, calcite and marble. They wanted to see if using these ingredients improved corrosion protection in the coatings.
Much effort has been put into developing new organic coatings to protect metal from corrosion in recent years. These coatings are usually cheaper to produce and more environmentally friendly. The most common organic material used in such coatings is calcium carbonate. It comes from a number of sources and has useful properties.
The different carbonate sources were tested with fourth different techniques. X-ray diffraction (XRD), X-ray fluorescence, scanning electron microscopy (SEM) and transmission electron microscopy (TEM) were all used to analyse the sources. The three calcium sources were then used to produce solvent based coatings. They were made using oil modified soybean dehydrated castor oil alkyd resin.
The coatings were then tested using three methods, immersion test, electrochemical impedance spectroscopy and SEM/EDAX. They were looking to see how well the coatings containing the three calcium carbonate sources protected against corrosion. The results showed that the egg shell was the best of the three. Its corrosion efficiency was due to its unique particle shape structure.
The study is published in: Progress in Organic Coatings Volume 128, March 2019, Pages 168-180.