Modified Taber apparatus and new test geometry to evaluate the reduction of organic coatings corrosion protective properties induced by abrasive particles

Organic coatings are one of the most common methods used in the protection from corrosion of industrial components. In many applications, the protective properties against corrosion are associated with several other properties, including resistance to abrasion and particle impacts. This is particularly important for the automotive and naval industry, and those applications that involve abrasive phenomena, such as presence of dust, sand or grains of hard material.The Taber test is among the most common tests to evaluate the abrasion resistance of coatings.In a previous work it was shown that electrochemical tests, after Taber Abraser standard test, allowed the evaluation of the decrease of corrosion protection properties. Nevertheless, assessment of the damage was carried out step by step, removing the samples from the abrading apparatus.The aim of this study is the evaluation of the possibility to measure in continuous, using electrochemical tests, the decrease of protection properties of an organic coating, caused by abrasion of artificial sand. A modification in the design of the standard Taber Abraser apparatus allowed the electrical contact between the substrate of the sample and the electrochemical equipment. Following the newly designed set-up, it is possible to evaluate the electrochemical properties of the system without removing the sample from the abrading system. A change of the geometry of the coated sample was also necessary, in order to build the cell. The latter contained the slurry made of a corrosion limited aggressive solution and the abrading sand.The impedance measurements were carried out without removing the coated samples from the Taber apparatus and using the abrading slurry as electrolyte. Useful information about the damage induced on the coated samples were recorded.