Hydrophobic coatings developed by the University of New Mexico protect industrial ceramics from thermal shocks

Ceramic materials are used in the nuclear, chemical and power generation industries because of their ability to withstand extreme environments. However, at high temperatures, ceramics can easily break due to thermal shocks caused by rapid temperature change events, such as cold water droplets touching the hot surface. In a novel interdisciplinary approach, engineers at the University of New Mexico reported in the journal American Physical Federation Progress, part of the American Physical Federation (AIP) Publishing Group, a cheap, simple hydrophobic coatingto prevent ceramic
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"We used exactly the same material, but controlled the heat transfer, allowing the ceramic to experience a milder temperature gradient and reduce stretch stress, thereby greatly improving thermal impact behavior." Youho Lee, one of the authors of the paper, said.
shock is a phenomenon that no new chefs who don't realize that glass is very sensitive to sharp temperature changes usually experience in the kitchen. If the glass casserole, which has just recovered from oven heat, is hit by cold water, a sudden drop in surface temperature can create an uneven temperature gradient inside the material, triggering stretch stress and eventually rupture. The same thermal shock sensitivity can also affect the life of industrial ceramics.
from an interdisciplinary academic background, Lee decided to explore the effects of heat transfer on ceramic thermal shocks. He analyzed heat transfer by capturing high-speed video of the impact of water droplets on heated ceramic surfaces. "When the heat transfer is fast, the collision instantly produces violent bubbles and jet streams on the surface."
study found that these faster heat transfer patterns corresponded to a decrease in material strength. When the ceramic is heated to 325 degrees C, a more intense droplet dynamics process (indicating faster heat transfer) is occurring, and the material strength is reduced accordingly. However, the material strength appears to be less affected by thermal shocks at temperatures above 325 degrees C, while droplet dynamics change to form a more visible vapor film.
To reduce heat transfer and the thermal impact that ceramics experience at up to 325 degrees C, Lee leverages some of the basics of nuclear engineering, which means that the two-phase heat transfer rate can be reduced by driving water away from the surface to form an insulated vapor film. To do this, he applied nanoparticles to the ceramic surface, creating a dredging surface of the nanostructure. When the test was repeated on a ceramic material with a new coating, the water drop dynamics were greatly altered and no violent foam spewed out. The formation of the steam film was observed. The key is that the ceramic with the new coating does not change in strength after the water droplet impact.
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