In 1960, the first metallic glass was developed at the California Institute of Technology. A metallic glass is an alloy that’s been heated up and then cooled down very quickly so that it doesn’t have a chance to form crystals, allowing the material to keep its amorphous structure. Thus, metallic glass is stronger than steel or titanium and just as tough, and 20 times stronger and stiffer than plastic. Metallic glass is an ideal material for everything from cellphone cases to aircraft parts.

The problem with metallic glass is that it’s difficult to mold and shape. Heat takes time to distribute through it, so the glass is generally molded at temperatures above 1000 degrees Celsius, which is hard on molds and is too expensive and impractical. However, now researchers have found a cheaper way to produce metallic glass. The researchers found that if they heated and processed the metallic glass fast enough, they could heat the metallic glass to a liquid state that’s fluid enough to be injected into a mold and can freeze before it crystallizes.

“We’ve taken the economics of plastic manufacturing and applied it to a metal with superior engineering properties,” says William Johnson, the Ruben F. and Donna Mettler Professor of Engineering and Applied Science. “We end up with inexpensive, high-performance, precision net-shape parts made in the same way plastic parts are made—but made of a metal that’s 20 times stronger and stiffer than plastic.” A net-shape part is a part that has acquired its final shape.

To heat the material uniformly and rapidly, they shot a high-energy electric pulse into a small rod of metal alloy, to a temperature of 550 degrees Celsius in only half a millisecond. Then, the softened glass was injected into a mold, the desired shape formed and cooled in 40 milliseconds. Because the material can be heated uniformly, only half the temperature is needed. This also means the materials needed to form the mold can be less expensive and replaced less often.

With metallic glass being 20 times stronger than plastic and potentially becoming just as cheap to produce, we would most likely see it replace plastic in products to make them stronger. Like Apple is using a type of Liquid Metal in the iPhone so their screens don’t break so easily. The researchers are publishing their findings in the journal Science.

Photo: A metallic-glass rod before heating and molding (left); a molded metallic-glass part (middle); the final product with its excess material trimmed off (right). [Credit: Marios D. Demetriou]

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Ready for another green energy alternative? You may already be familiar with solar panels and may have just equipped your home with geothermal heating, but what can you do to convert the sun’s rays into energy that is easily stored and transported?

Researchers from the United States and Switzerland have reportedly put together a prototype generator that offers an entirely different way to capture the sun’s energy compared to a conventional photovoltaic (solar) panels. The prototype has a quartz window and a cavity for focusing sunlight into a cylinder lined with cerium oxide (ceria).

When the sun’s rays heat up the ceria, it will thermochemically break down the water and carbon dioxide that is being pumped into the cylinder. The net result is carbon monoxide and hydrogen, which can then be converted into liquid fuel. This hydrogen feul can then be used with hydrogen fuel cells. Alternatively, the hydrogen-carbon monoxide mixture could be converted into syngas, a combustible gas.

“The chemistry of the material is really well suited to this process,” says Professor Sossina Haile of the California Institute of Technology (Caltech). “This is the first demonstration of doing the full shebang, running it under (light) photons in a reactor.”

Now, I’m no scientist, but there are at least two big concerns about such a generator. First, it needs energy to pump in the source materials (water and carbon dioxide). Second, it still outputs carbon monoxide, which to my knowledge, isn’t really a good thing unless you have some sort of greenhouse. At this stage of the game their prototype is very inefficient; fuel created harnesses only 0.7% to 0.8% of the solar energy taken into the vessel. The good news is that ceria is really abundant, so getting that stuff wouldn’t be too difficult.

[GizMag via BBC]

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