A new sprayable ice-shedding coating is 100X stronger than any other

When Air Florida's Flight 90 crashed into the Potomac River on January 13, 1982, killing 78 people, nobody at that time suspected that the catastrophe had been triggered by ice formation on the wings. Over the years, the incident led to better de-icing technologies and procedures, but ice crystal accretion remains a serious hazard in aviation.

Now engineers at the University of Houston have developed a sprayable ice-shedding material that is 100 times stronger than any other. The coating material has been tested by Boeing under erosive rain conditions at 385 mph (619 kph) and has outperformed current state-of-the-art aerospace coating technologies.

Fracture-controlled surfaces

In the current study, engineers developed a material that prevents dangerous ice buildup while limiting unwanted environmental effects. They call this coating material a "fracture-controlled surface." The material uses varying chemical and mechanical compositions to initiate crack formation at the interface, direct energy toward those cracks, and accelerate their growth.

"We developed a new concept in which, through material design, you can significantly accelerate the crack formation and growth and easily remove external objects from the surface. This concept is implemented to develop materials that are highly durable, and ice does not attach to these materials. Fracture-controlled surfaces provide a rich material platform to guide future innovation of materials with minimal adhesion while having very high durability," says Hadi Ghasemi, Cullen Associate Professor of Mechanical Engineering.

The coating material comprises three phases: a matrix phase, a crack formation phase, and a third phase for guiding crack propagation.

It works on the principle that force must be applied to remove an external solid object from a surface, such as ice from an airplane wing. This force encourages the formation of cracks at the interface. Once that crack starts, it can quickly grow until the ice completely detaches from the surface.

According to the paper, detachment can be accurately controlled and accelerated using this new concept.

A necessary solution

From airplane wings to overhead powerlines to the giant blades of wind turbines, a buildup of ice can cause problems ranging from impaired performance all the way to catastrophic failure.

Scientists and engineers have been waging a quiet but determined battle against this problem. So far, a wide range of materials with ice-shedding characteristics have been developed, but many tend to have very low durability, limiting their effectiveness.

"The primary challenge in developing ice-shedding materials is finding materials with both low ice adhesion and good durability," said Ghasemi.

The new material offers both. It can withstand a pressure of 2000 psi and droplet velocities of 395 mph (619 kph)without mechanical damage while maintaining excellent ice-shedding characteristics.

This new concept of fracture-controlled materials paves the way for innovative materials for aerospace, energy, and other industrial applications where icing is an issue.

A thin coating of ice on solar panels can wreak havoc with their ability to generate electricity. Thin layers of ice on the vanes of wind turbines could lead to an 80% drop in power generation which can be avoided through these new coating materials.