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Microwaves heating up ultra-high-temperature (UHT) ceramics industry – Science Nation

Microwaves heating up ultra-high-temperature (UHT) ceramics industry – Science Nation


♫MUSIC♫ VOICE: 4, 3, 2, 1, and liftoff! MILES O’BRIEN: Watch a launch like this and you can’t help but wonder – how do they do that? Make engine parts so durable they can withstand a fiery inferno? Well, those are no run-of-the mill nozzles on the rockets. They’re made of high-performance ceramics. HOLLY SHULMAN: When you’re trying to push materials to extreme limits, most metals will start to soften and give out at high temperatures. Ceramics are very stiff. MILES O’BRIEN: A key to building denser, stronger materials that won’t fail or fracture under extreme conditions is the manufacture of ultra-high temperature, or UHT, ceramics. HOLLY SHULMAN: It’s defined as over 1800° C in processing. That’s, that’s extremely hot – most people, you think in terms of red hot as 1000° C. Good, excellent… MILES O’BRIEN: With support from the National Science Foundation, materials scientist Holly Shulman and her team at a company called Ceralink are developing UHT ceramics using a new method that harnesses the power of microwaves. HOLLY SHULMAN: So, instead of the way food heats, which is based on the water heating within the food, we can actually make that work in ceramic materials to heat them internally and cause them to densify very quickly and with huge energy savings. MILES O’BRIEN: At Ceralink, the machines they use to make the UHT ceramics still fire up to high temperatures. But, rather than combining the heat with high pressure to push the atoms in the material together and make it super hard and strong, they use microwaves. It’s a process called “enhanced diffusion.” HOLLY SHULMAN: So, instead of having to use high pressures, we are investigating the use of microwaves for enhanced diffusion and then it can be done at atmospheric pressure. MILES O’BRIEN: The goal is to make the industrial manufacture of high quality UHT ceramic parts faster and cheaper. Take this silicon carbide filter designed to strain molten metal. It gets extruded in an additive manufacturing process called robocast, then fired in Ceralink’s UHT microwave-assist furnace. HOLLY SHULMAN: So, it’s like squeezed out of a tube of toothpaste or play dough that you can imagine, and it builds up a part in three dimensions. The firing by using our type of technology is much faster. MILES O’BRIEN: Faster, cost-effective methods to bring ultra-high temperature ceramics to marketplace – it’s an idea that’s heating up. For Science Nation, I’m Miles O’Brien.

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