Perfect Combination of LBL with Sol–Gel Film to Enhance the Anticorrosion Performance on Al Alloy under Simulated and Accelerated Corrosive Environment

Abstract

Given their outstanding versatile properties, multilayered anticorrosion coatings have drawn great interest from researchers in the academic and engineering fields. However, the application of multilayered coatings is restricted by some limitations such as low interlayer compatibilities, the harsh preparation process, etc. This work introduced a composite film fabricated on a 2A12 aluminum alloy surface, including an anodic oxide film, a sol–gel film, and a layer-by-layer (LBL) self-assembling film from bottom to top. The microstructure and elemental characterization indicated that the finish of the coating with the LBL film resulted in a closely connected multilayered coating with a smoother surface. The anticorrosion performance was systematically evaluated in the simulated corrosive medium and neutral salt spray environment. The integrated coating with the LBL film presented an excellent anticorrosion ability with system impedance over 108 Ω·cm2 and a self-corrosion current density two orders of magnitude lower than that of the other coatings. After the acceleration test in a salt spray environment, the multilayered coatings could still show a good protective performance with almost no cracks and no penetration of chloride ions. It is believed that the as-constructed multilayered coating with high corrosive properties and a fine surface state will have promising applications in the field of anticorrosion engineering.

Sol-Gel Materials for Electrochemical Applications: Recent Advances

“…Table 2 presents the results of the study on corrosion resistance using hybrid sol-gel coating on aluminum substrates. Zhao X et al [76] fabricated an LBL anodic composite film on the surface of 2A12 alloy by the sol-gel method. Primarily, an anodic porous oxide layer and a subsequent homogeneous aluminum sol-gel coating were created on the alloy substrate, after which the sol-gel composite film was self-assembled by LBL with PAA and PEI.…”

A review of current knowledge and future trends in polymer/boehmite nanocomposites

“…In addition to anti-corrosion, self-healing coatings of the polymer/boehmite nanocomposites have also been prepared. 99,100 The self-healing polymer/boehmite coatings may be used to prevent the long-time degradation and microcracks in the metallic and engineering structures. [100][101][102] Such anti-corrosion and self-healing coatings are useful for the automotive and aerospace structural parts.…”

Formation of Self-Assembled Anticorrosion Films on Different Metals

“…One of the mentioned methods that can increase the desired anticorrosion properties is the sol–gel technique, especially when it incorporates inhibitors and/or nanoparticles in a hybrid sol–gel system [ 23 , 24 ]. The sol–gel thin films adhere well to metals as well as to topcoats; this is important from the industrial application point of view.…”