Self-healing Coating by Using Pore of Porous Film Formed on Al Alloy Anodized and Effect of Pore-size on Self-healing Property of Coating

Abstract

In this study, economic and advanced coating with self-healing property for corrosion protection of Al alloy were developed. This coating can be formed on Al alloy by following procedure. The porous type of anodic oxide film was formed on Al alloy surface and pores of porous film were filled with a healing agent of coating. And then, the polyurethane coating was formed on this surface. From results of this study, it is clear that the scar formed on the specimen surface covered with this self-healing coating, by damaging mechanically, was covered by self-healing structure. This structure may form by the reaction between healing agent and vapor in air. Corrosion protection of the specimen covered with this coating, can also be kept high by the self-healing property of this coating, if this coating was damaged.

Self-Healing Coatings Consisting of an Outer Electrodeposited Epoxy Resin Layer and an Inner Porous Anodic Oxide Layer with Healing Agents for the Corrosion Protection of Al Alloys

“…This is discussed in Section 4.1. In previous studies, the authors of this paper found that a Cu 2+ /Cl − solution is significantly useful for detecting imperfections in oxide films on Al alloys [18,19,22,23]. Cu 2+ and Cl − ions synergistically enhance the local corrosion of Al alloys through imperfections.…”

“…From the EIS data shown in Figures 5 and 7, an equivalent circuit can be assumed, as shown in Figure 8 [22,[31][32][33][34]. 1000 Hz.…”

“…From the EIS data shown in Figures 5 and 7, an equivalent circuit can be assumed, as shown in Figure 8 [22,[31][32][33][34]. The equivalent circuit is presented by a series connection between Rs, the solution resistance in the crack formed by scratching, and CPE, the constant phase element of the anodic oxide films remaining unremoved at scratched area, which has a parallel connection with Rox, the resistance of the anodic oxide film at the scratched area.…”

“…However, the synthesis of the capsule includes relatively complex processes and gives low yields of capsules. In order to solve this problem, the authors developed a new type of self-healing coating [22,23]. In the new process, Al alloys are anodized in oxalic acid solutions to form porous anodic oxide films [24][25][26][27][28][29][30], and the pores of the anodic oxide film are filled with healing agents.…”

Self-Healing Coatings with Double-Layered Structure for Corrosion Protection of Aluminum Alloys

“…The second self-healing coating technique is the filling in nanopores of a porous type of anodic oxide film on Al alloys with healing agents 11,12) (Fig. 2(d)).…”