PROCESS FOR EVALUATING CORROSION RESISTANCE OF COATING

摘要

The present invention is directed to a process for evaluating corrosion resistance of coated metals substrates, such as autobodies at accelerated rate. An anode and cathode coated with protective coating being tested are exposed to an electrolyte in a chamber of a corrosion resistance evaluator. These coatings are provided with predetermined and standardized defects, such as micro-holes to accelerate the corrosion of the underlying metal substrate in a predictable and repeatable manner. The coated cathode/anode pair is subject to a start-up period followed by series preset DC voltages modulated in a stepwise manner for preset durations that are interspaced with recovery periods. The impedance data collected are then used to arrive at the corrosion performance resistance of the coating applied over the cathode/anode pair. The foregoing evaluator substantially reduces the time required to test corrosion from several days (40 plus days) to few days (about two days).