999 publications from this institution
Self-healing coatings with capsules containing healing agents have been developed for the corrosion protection of metal. In this paper, polyurethane capsules were synthesized under different conditions to examine the size and shape of capsules, and self-healing ability of coatings with capsules dispersed was examined after damaging the coated layer by scratching with a cutter blade. The size and shape of capsules depended on the concentration of chlorobenzene in cyclohexanone used as a solvent of prepolymer solution. The capsule formed with 70 % of chlorobenzene gave a self-healing capability to the coated layer by releasing the healing agent after damaging. The amount of glycerol added for the formation of the polyurethane capsule shell affected the self-healing ability of the coated layer. The coating with the capsule formed with small amounts of glycerol showed a high healing ability, while, with large amounts of glycerol, the self-healing ability was relatively low.
Electrochemical scanning tunneling microscopy is proved to be a powerful tool for providing valuable topographic information to study in situ the local corrosion properties of polycrystalline materials. It was applied to analyze the susceptibility to intergranular corrosion of different types of grain boundaries of microcrystalline copper in HCl and combined with electron backscatter diffraction to link the observed corrosion differences to a specific type of grain boundary. The superior resistance to intergranular corrosion of coherent twin boundaries over random grain boundaries is demonstrated.
