Sugar coating technology makes planes invisible

Scientists have developed an aircraft coating made of millions of tiny, hollow carbon spheres packed tightly into a single hexagonal layer made of carbonized sugar that could make aircraft invisible to radar.

Hollow carbon spheres from a scanning electron microscope. Photo: D. Bychanok

According to Science Daily, these spheres will absorb all radiation in the Ka band (frequency 26.5 – 37 GHz or wavelength 7.5 – 10 mm), the frequency range often used by the military for radar. In addition to aircraft and military equipment, anti-reflective coatings can also be used on many other surfaces including computers and phone screens.

Based on experimental and modeling results, scientists found that using hollow carbon spheres with a diameter larger than the spherical structure in moth eyes and an optimal thickness, arranged in a hexagonal pattern, can achieve near-perfect microwave absorption. In nature, thanks to these special eyes, moths can absorb light to see better in the dark and avoid bats that eat them.

To make the coating, scientists from the Institute of Nuclear Problems at Belarusian State University coated biopolymer beads with sucrose, a form of sugar that is easily extracted from natural sources.

The beads are then burned in a special process called pyrolysis, which turns the plastic inside into a gas and releases it, while also burning the sugar into carbon. The result is hollow carbon spheres. These spheres are then further pyrolyzed at 900 degrees Celsius in a nitrogen atmosphere to create a glass-like material.

Using a coating made this way, it was able to absorb about 95 percent of 30GHz radiation, according to Dzmitry Bychanok, the study's lead author. The team's next plan is to develop the material from two dimensions to three-dimensional structures.

According to VnExpress