New metal coating self-heals scratches, cracks within seconds

Corrosion in metals can lead to entire structure failure. To avoid this, scientists have created a new form of material that is able to heal itself in matter of seconds.

Researchers from the Northwestern University have created a new coating for metal, which is not only unbreakable, but also when scratched, scraped, or cracked, can self-heal within few seconds.

Lead researcher Jiaxing Huang told Digital Trends, “We made self-healing coatings on metal surface based on oil. The unusual part is that the oil coating does not drip, sticks very well, and at the same time can rapidly heal when scratched. Such coatings can protect metal surface from highly corrosive environment[s].”

The material was created by modifying oil with lightweight hollow particles in the form of small graphene capsules, measuring only tens of micros in size. The capsules form a network in the oil, hence preventing the oil film from shrinking or dripping.

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“When a boat cuts through water, the water goes right back together,” Huang told New Atlas. “The ‘cut’ quickly heals because water flows readily. We were inspired to realize that fluids, such as oils, are the ultimate self-healing system.”

The capsules, however, still allow oils to flow when a scratch breaks the network, and thus healing the damaged area. The material is also able to heal repeatedly even after being scratched numerous times on the same spot within seconds, on various metals including steel, brass, and aluminum.

The material for now has only been tested on small-sized samples like metal plates or wires. In future, the material could prove to be useful as a temporary anti-corrosion solution for metals that are placed in highly corrosive environments, as per the paper published in the journal Research.

“We are interested in [the] anti-fouling properties of such coatings. We also wish to broaden the scope of suitable lightweight particles or to find ways to mass produce such graphene capsules. This is such an intriguing, yet seemingly simple system [that] we wish to gain much better understanding of why it works so well,” said Huang.