Back WU team's quasicrystal research gets notice nationally. St. Louis Post - July 7, 2003 Findings could help with fuel cells in cars, prolong artificial joints By Angela Vierling The king's blacksmith used goat's urine. These days Washington University's Ken Kelton uses an electrostatic levitator. In both cases, the two were trying to control a process called crystallization to make a better product. The smithies wanted to make better swords. Kelton's research could have an impact on matters as diverse as energy consumption and the manufacture of artificial joints. it's featured on the cover of the July issue of Physics today and was highlighted in a recent issue of Science magazine. In medieval times, the blacksmiths found that they could make weapons stronger by cooling redhot metal in a bath of urine or eve blood. The urine added nitrogen to the sword, changing the way the metal crystallized as it cooled. Instead of urine, Kelton's research team uses "supercooling" - cooling liquid metal below its freezing point without allowing it to solidify. In the process, the researchers have used the electrostatic levitator to help substance, called a quasicrystal. In his State of the Union address this year, President George W. Bush announced an initiative to decrease dependence on foreign oil by developing hydrogen fuel cells to power cars. These fuel cells would use a chemical reaction, like in a battery, to produce electricity. The difficulty is that hydrogen is hard to store in a fuel cell. Kelton's quasicyrstals can trap and hold a lot of hydrogen on the molecular level, And when graduate student Geun Woo Lee told Kelton there were quasicrystals in their experiment, Kelton didn't believe him, either. Kelton was skeptical because quasicrystals break the rules about what shapes can grow into crystals. But their unwidely nature actually helped Kelton and his colleagues solve the mystery of supercooling. As the liquid metal in their experiment cools, the molecules begin to arrange themselves into quasicrystals. To freeze into solid form, the molecules must scramble to change from the quasicrystal form into more normal crystal shapes. Naturally lazy, the liquid instead tends to stay liquid, even at temperatures well below the metal's freezing point. Supercooling is hard to study because melting and cooling metal in a container can contaminate the experiment. If you pour a beer, you'll notice that the bubbles seem to flow out of certain spots on the glass. Carbon dioxide is crystallizing in the beer. The carbon dioxide crystallizes where it's easy - where there is an impurity like a bit of lint from a dishrag or a speck of dust. To avoid this kind of contamination, Kelton worked on an electrostatic levitator from NASA's Marshall Space Center in Huntsville, Ala. The levitator can suspend a bead of metal in midair, allowing researchers to heat and cool it without the troublesome container. Jan Rogers, who runs the levitator program, says the idea behind it is simple: "When you take your socks out of the dryer...,you can essentially repel objects." Static electricity will usually make your socks stick to other clothes. But when handled properly, two socks also can push each other away. The levitator does the same thing to keep a bead of metal hovering in the air. "This containerizes procedure... allows us to make new materials," Rogers said. The electrostatic levitator was used in the development of a metallic glass that is now manufactured by Liquidmetal Technologies in Tampa, Fla. This May, the company teamed up with Rawlings Sporting Goods to produce a new line of baseball bats that reduce the energy lost when the bat hits a ball. Studying metal in the levitator also may help the National Aeronautics and Space Administration get to Mars. According to Kelton, sending anything bigger than a rover to Mars will require using rockets that operate at much higher temperatures than those now in use. Container-free methods are essential when studying the effects of extremely high temperatures on metals, in order to avoid melting the container. Reporter Angela Vierling go to top