بررسي رفتار الكتروشيميايي امپدانس رنگدانه كرومات روي و نقش محافظتي آن به عنوان پوشش اوليه

Invesitigation on the Behavior of Zinc Chromate Pigment and its Protective

In this study, the portective performance of zinc chromate at various PVCs (Pigment Volume Concentration= 25, 30, 35, 40, 45, 50) in epoxy ester resin was evaluated through electrochemical impedance technique. The obtained data were compared with those of routine tests, including adhesion and salt spray fog chamber. The results show that in electrolyte with 3.5% sodium chloride content, the calues of log Z decrease for the samples exposed to salt spray for 24 hours, comparing with the blank, while the behavior of samples exposed to salt spray chamber for two weeds increase it. These findings indicate that the impedance value changes in inverse proportion to the amount of water absorption, dielectric constant, and electrical capacitance of the coating. The results imply that the best perfamance of this primer is in the PVC range of 30-40.