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The desert scorpion, champion survivor of a brutal corrosive environment, has a thing or two to teach scientists about protecting material surfaces.
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Per-Anders Olsson / Creative Commons |
| Androctonus australis is giving up some protective secrets to materials researchers in China. |
Researchers at China's Jilin University are studying the fat-tail scorpion—resident of the Arabian and Sahara deserts—to see how its armor holds up so well in a punishing environment that whips paint from steel and clogs and abrades machinery.
The secret: tiny grooves and granules in the scorpion exoskeleton that change airflow to deflect sand from the surface.
Military Equipment Potential
The grooves apparently work best when set at a 30-degree angle to the direction of airflow, although any grooves in the shell are better than none, the researchers report in “Erosion Resistance of Bionic Functional Surfaces Inspired from Desert Scorpions,” published in the science journal Languir.
The research holds important implications for protecting both internal components and external surfaces of engines, pipes, turbines, rotor blades and military equipment deployed in desert environments, the team reports. Such environmental assaults are a chief cause of equipment failure in such locations.
Pet Shop Pursuit
The team’s investigation began by scouring the pet shops of Changchun, where the university is located, for Androctonus australis, The Economic reports.
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Han Zhiwu et. al. |
| The grooved microtexture of a scorpion’s exoskeleton stands up to the corrosive desert environment. |
Microscopic examination of the animals—live, but unconscious—under UV light gave the team a sharp look at their armor. (The exoskeletons are composed of a sugar-based polymer called chitin that fluoresces.) What they found were dome-shaped granules, 10 microns high and 25 to 80 microns across.
Testing
The scientists then used a 3D laser-scanning system to map the armor’s surface features and “plugged the result into a computer program that blasted the virtual armor with virtual sand grains at various angles of attack,” The Economist explained.
That work revealed that the armor’s granules were disturbing the air flow in ways that reduced erosion near the surface.
The research then moved to a wind tunnel, where grains of sand were fired at smooth and etched steel samples. After five minutes in the simulated sandstorm, the samples were weighed, to measure their erosion.
The microtexture most similar to the scorpion’s armor—with grooves 2mm apart, 5mm wide and 4mm high—fared the best.
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