Evaluacion de pinturas mediante metodos electroquimicos y ensayos acelerados de corrosion

The behavior of paints under service conditions has been evaluated using electrochemical essays and accelerated corrosion laboratory tests. Tin plate samples covered with alkydic, vinilic and epoxy paints of 25 (mm) and 50 (mm) thickness were employed as testing materials. Stationary polarization curves and the evolution in time of corrosion potential, both recorded in 3.5% pp. NaCl pH = 2 solution, were the electrochemical techniques used. Accelerated tests were performed through the Cebelcor method (0.001M NaCl) and salt spray tests (3.5% pp. NaCl). Also, some samples were exposed to natural marine environment close to the coast of Valparaiso-Chile (Lat 30° and Long 70°). Results show a good correlation between the accelerated and long term test. The results indicate that the highest protecting behavior was obtained using the vinilic paint, followed by the epoxic paint. The lowest protecting behavior was shown by the alkydic paint.