Fabrication and corrosion resistance research of stearic acid-doped silane composite passivation film on electrolytic manganese

Abstract

To solve the pollution problem caused by chromate, developing a new type of chromium-free passivation method has been regarded as a valid strategy to environmentally develop the electrolytic manganese industry. Herein, a single dodecyltriethoxysilane (DTES) passivation film and stearic acid doped dodecyltriethoxysilane (DTES-SA) passivation film were successfully prepared by the facile impregnation method, and the two passivation films were detected by electrochemical and multiple characterisation methods. It was found that the doped passivation film compensated for the defects of the single silane exhibits better corrosion resistance than that of the single silane passivation film. Compared to the bare electrolytic manganese, the corrosion current density of the DTES-SA passivation film decreased from 4.081 × 10⁻⁵ to 2.457 × 10⁻⁶ A·cm⁻², and the contact angle significantly increased from 52.27° to 144.73°. Besides, it can be seen that the composite passivation film can effectively prevent electrolytic manganese from being corroded and oxidised.