Preparation and Mechanism Study of Phytic Acid and Azole Derivatives Composite Conversion Film

Abstract

To improve the problem of difficulty in forming a complete and dense conversion film on the copper surface when using phytic acid alone，the conversion films containing phytic acid (PA) and different azole derivatives were prepared on copper surface by impregnation method.The hydrophobicity，corrosion resistance and surface morphology of the conversion films were characterized by contact angle tester，electrochemical workstation，scanning electron microscope and energy dispersive spectroscopy (EDS).The film formation mechanism of PA+BTA conversion film with the best corrosion resistance was analyzed using X-ray electron spectroscopy (XPS).Results showed that the corrosion resistance of conversion films formed by adding different azole derivatives was improved.The contact angle of the conversion film with benzotriazole (BTA) and phytic acid reached maximum value (135.51 °)，and the corrosion current density reached minimum value (2.050 × 10-7 A/cm2)，while the impedance value exceeding 90 kΩ.By observing the SEM morphology of PA+BTA conversion film，it was found that the conversion film was evenly distributed and dense on the surface of copper substrate.XPS analysis of the PA+BTA conversion film showed that both PA and BTA were involved in the formation of the conversion film.PA-Cu and BTA-Cu complexes were formed on the surface of copper substrate，which could effectively protect the substrate.

Keywords

•  phytic acid|benzotriazole|conversion film|corrosion performance|cu substrate