Solution‐Processed Nanocoating of Ca2Nb3O10 and Polydopamine for Anticorrosion on Magnesium Alloy

Abstract

2D materials have exhibited great potential for applications in anticorrosion nanocoatings. However, the nanocoating of prefocused graphene shows “corrosion‐promoting activity” due to its high conductivity. Metal oxide nanosheets obtained by delaminating layered oxides have been another attractive candidate. This study demonstrates a water‐based Ca2Nb3O10 (CNO) ink spray coated on magnesium alloys to form a continuous coating without complex functionalization and structural control. The composite coating of Ca2Nb3O10 (CNO) and polydopamine (PDA) is fabricated by combining spray‐ and dip‐coating methods. The surface composition and microstructure of the as‐prepared coatings are characterized by X‐ray diffractometry, Fourier transform infrared, X‐ray photoelectron spectroscopy, scanning electron microscopy, and energy‐dispersive spectrometry. The anticorrosion performance of the composite coating is evaluated by potentiodynamic polarization, electrochemical impedance spectroscopy, and salt spray tests. The electrochemical results show that the CNO/PDA heterostructure coating provides an enhanced corrosion inhibition efficiency (99.62%) with a corrosion current density of 5.49 × 10−7 A cm−2, three orders of magnitude lower than bare AZ31. The immersion tests before and after heat treatment and salt spray tests indicate that the composite coating has good stability and long‐term anticorrosion performance. Solution‐processed nanocoating and extensible materials design provide a green and facile route to anticorrosion nanotechnology for industrial demands.