MEAM Seminar: “Room-Temperature Electrochemical Healing of Structural Metals”

Many biological materials and organisms, such as bones and mollusks, possess the capability to heal and repair fractures at room temperature or at low homeostatic temperatures (∼ 20 ◦C – 40 ◦C). While this healing capability has inspired many advances in room-temperature self-healing polymers, metals have proven more difficult to heal at room temperature due to the very slow transport rates of metal atoms. This talk showcases a new rapid, effective, low-energy, and room-temperature approach to heal structural metals using nickel electrodeposition while mimicking the transport-mediated healing of bone. A polymer coating on the structural metal enables selective healing only at the fracture site, while electrochemical reactions transport nickel ions from a nickel source to fractured areas. Using this approach, cellular nickel fractured by either tension or scission is shown to recover 100% of its tensile strength in as little as 10 and 4 hours of healing, while consuming several orders of magnitude less energy than many previously reported metal healing techniques. This approach is extended to the healing of low-carbon steel, a widely used structural metal, while elucidating the effect of ion transport and electrolyte chemistry on morphology and strength in fractured steel repaired with nickel electrodeposition. This work opens the possibility of healing a variety of structural metals using selective electrodeposition. With its low energy and time requirements, as well as its effective recovery of strength, electrochemical healing can be used to extend the service life of structural parts, repair alloys vulnerable to thermal cracking, and more efficiently employ scarce resources in energy-constrained systems or in remote environments.