Titanium makes move toward mainstream
Aeronautical engineers use titanium because it’s strong, lightweight, and corrosion-resistant. Golfers like titanium in their clubs for similar reasons. So why doesn’t everyone drive a car made of this supermetal? Sadly, titanium possesses one fatal weakness—its cost.
Now, a novel method for producing titanium could make it more competitive with stainless steel, researchers claim. The cheapest form of titanium today costs at least several times as much as stainless steel. The new process could make as much titanium in a day as the usual method does in a week and could drop its price to one-third the current cost, says Derek J. Fray of the University of Cambridge in England.
Titanium’s boutique status stems from its production challenges, not its availability. Titanium dioxide, familiar as white pigment in paints, is abundant in Earth’s crust. Yet wrenching titanium from titanium dioxide has traditionally required a difficult, time-consuming chemical process, that also suffers from the disadvantage of using and producing corrosive and volatile substances.
As an alternative, researchers have sought to use electric current to obtain titanium. In the 1880s, scientists developed just such an electricity-based extraction method for aluminum. The price of aluminum subsequently fell so much that people could wrap sandwiches with it.
Until now, however, electrochemical production of titanium hasn’t offered much benefit over the strictly chemical method, says Fray. In the new approach, solid pellets of titanium dioxide are fed directly into liquid calcium chloride. Then, an electrical current separates the oxygen from the pellets, leaving behind solid titanium metal, Fray’s team reports in the Sept. 21 Nature.
Preliminary experiments with a scaled-up process suggest that the same procedure can produce kilograms of titanium, the researchers add.
“I think it looks extremely promising and potentially could result in a significant reduction in the price,” comments Harvey M. Flower of the Imperial College of Science, Technology and Medicine in London. “And that would dramatically affect the potential market for titanium.”
One of the largest potential uses is in car manufacture, notes George Zheng Chen, a coauthor of the report and a materials chemist at Cambridge. Replacing steel car parts with titanium would lower a vehicle’s weight, reducing both fuel use and emissions, he says.
