Self-Healing Metal Coating
A self-healing metal coating has been devised by intrepid researchers at the Fraunhofer Institute for Manufacturing Engineering and Automation in Stuttgart, Germany.
The self-healing coating is just 15 micrometers thick, so it is not capable of any sort of large-scale repair. However, if the coating is scratched, polymer capsules just a few hundred nanometers thick rupture and release their healing contents - a polymer that seals the crack or even corrosion-resistant liquids.
(Self-healing metal coating)
The liquid inside the nanocapsules could be tailored to a variety of purposes. For instance, capsules in the plating of ball bearings could be filled with mineral oils to make the bearings self-lubricating. Capsules filled with colored liquids or scented oils could make metal parts that change color or release an odor when they are damaged. Better yet, several different types of capsules could be incorporated inside a metal layer, Holeczek says. For instance, it may be possible to "use color or scent in an upper layer to signal wear or damage and use some inhibition agent in a deeper layer to prevent severe damage."
I love self-healing materials of all kinds, and I can't wait to own them and have them work for me. See these articles on Nanotech Self-Healing Houses and Self-Healing Polymer Autonomous Material System for variations on self-healing materials. In 1962, sf author JG Ballard wrote about a material with similar uses in self-healing houses; he called it plastex.