The superpowers of coatings make the impossible possible

Jet engines are one of the most amazing feats of engineering ever created by humans.

But jet engines shouldn’t be possible, says Ben Beck, director of materials research at Micro Materials, an equipment testing company in Wales.

“The incoming air is hotter than the melting point of the metal underneath, which is not good, of course,” he explains, noting that this air reaches temperatures much higher than 1,000 degrees Celsius.

Jet engine designers have overcome this problem through application Heat resistant ceramic coatings to the motor blades. Now, researchers are developing stronger coatings that allow engines to run hotter.

“If you make it hotter, there will be huge savings in fuel and carbon dioxide,” says Dr. Beck. It is estimated that by increasing the temperature by just 30°C or so, you might get a fuel saving of 8%.

This is the power of coatings – they radically change the functionality and capabilities of the base material. Few people realize how important they are, but these overlays and veneers can enhance high-performance machinery, or ensure expensive equipment survives the harshest environments.

Dr. Beck and his colleagues were tasked with pushing the coatings to their limits, in order to find out how strong or effective they were. His clients don’t always get the results they want. “We’ve broken your cover,” he recalls telling a missile manufacturer a few years ago. “They went off in a rage,” says Dr. Beck.

Besides exposing the paint to high temperatures, Micro Materials also has a “woodpecker” device, a small diamond pen, that repeatedly taps the paint in random locations to test its durability.

Recently, the company worked with UK-based Teer Coatings to test a product that could be applied to satellite components including gears and bearings used in various moving parts.

It’s a difficult task, says the company’s Xiaoling Zhang, because the coating must protect these components before launch (when they are exposed to atmospheric humidity at ground level), as well as in orbit, against dust particles and radiation in space. However, it claims that the company achieved the desired results.

But besides protecting spacecraft, coatings can also prevent astronauts from getting sick.

Biofilms – dark accumulations of bacteria inside pipes – They grow faster in low gravity environmentsWhich could pose a problem for water supplies or machines that move fluids in space stations or future spacecraft, for example.

“Biofilms are known to cause mechanical failure,” says Kripa Varanasi of MIT. “You don’t want this.”

Professor Varanasi and his colleagues have developed a range of coatings that make surfaces slippery and thus resistant to biofilm formation. Tests of one of these coatings in an experiment aboard the International Space Station found that it does It worked as intended.

The idea behind the coating is to mix a solid and a lubricant. This is then sprayed on the inside of the pipe or tube, making the inside surface very slippery.

Professor Varanasi has previously made headlines for developing coatings similar to The insides of toothpaste containers – So you can get all the rest of the toothpaste out. He and his colleagues commercialized the technology through their spin-off company, LiquiGlide.

Perhaps slippage is an underappreciated trait. Nuria Espallargas of the Norwegian University of Science and Technology and her colleagues have developed a silicon carbide-based coating for equipment used to fabricate or repair aluminum.

It is a type of non-stick pan solution, which means that layers of molten aluminum do not stick to this expensive equipment. However, the exact performance of this particular coating is currently a mystery.

“To be honest, we don’t really know how this works, and the mechanism is currently unknown,” says Professor Espalargas.

However, the coating is commercially available through its separate company Seram Coatings. Atlas Machine and Supply, an American company that makes and repairs industrial machines, has tried it out.

“The real benefit is extending the life of the tools and improving the quality of the products being produced,” says Jeremy Rydberg, chief innovation officer.

Without paint, Atlas would have to rebuild the rotary tools it uses to fabricate aluminum every two days, he says. This costs $4.5 million annually. But the new paint means these tools last a full week, not just a few days, cutting rebuilding costs to about $1.3 million a year.

Coatings can do some amazing things, but they don’t always work as intended, notes Andy Hopkinson, managing director at Safinah Group, a company often called in to investigate if something goes wrong with coatings.

“We’re seeing a lot of problems right now with parking lots where their passive fire protection system is peeling,” he says, referring to the fire-resistant coating that is sometimes applied to concrete structures.

His company has also found that coatings applied to commercial ships do not always prevent barnacles and other marine organisms from attaching to the ship’s hull. This problem, known as biofouling, increases friction, i.e. the friction of the vessel The engine has to work harder – And burn more fuel.

Although coatings are available that promise to help, shipowners do not always choose the right paint for their vessel. This choice should depend on where the ship is sailing, how long it has to be idle rather than in motion, etc., says Dr. Hopkinson.

The cost of repairing such problems can reach several thousand, or even millions of pounds. “The cost of paint is usually between 1 and 2 percent of the project. The problem is that when things go wrong, the costs become enormous,” says Hopkinson.

However, researchers working in this field say that there are still many opportunities to improve coatings and develop new coatings that could significantly improve the performance of machinery or infrastructure in the future.