Titanium fuel tanks on Skylab.

Titanium Could Become Less Precious

Duffers of the world rejoice, the price of your next set of titanium-clad golf clubs may yet drop a couple of bucks. A new method to convert titanium ore into the metal, which is used for everything from sporting goods equipment to aircraft frames, could reduce the price of titanium two- to fourfold--if the process can be scaled up. That could make titanium cheap enough to replace stainless steel for a plethora of applications.

Titanium is an engineer's dream: It's light, strong, and resists corrosion. What's more, titanium-dioxide--the starting material--is abundant and cheap. But only a few tens of thousands of tons of the metal are used every year, compared to millions of tons of steel. The reason: Yanking oxygen atoms away from titanium-dioxide to yield the bulk metal is slow and environmentally hazardous, which drives up titanium's cost.

Searching for a better way to isolate metal titanium, a team led by materials chemists George Zheng Chen and Derek Fray of the University of Cambridge in the United Kingdom came up with an electrochemical technique, they report in the 21 September issue of Nature. The researchers start with an electrically conductive crucible made from titanium, inside which they place pellets of titanium-dioxide bathed in a molten salt of calcium chloride. They dunk a positively charged graphite electrode into the salt and pass an electrical voltage between the electrode and the side of the crucible. The voltage injects electrons into the oxygen atoms, allowing them to break free from titanium's hold and travel to the electrode, where they pick up carbon atoms from the graphite to form carbon dioxide. The result: bulk titanium without the mess.

In addition to generating fewer environmentally dangerous products, the process has the potential to produce titanium in a continuous process rather than by the batch. As a result, says Harvey Flower, a materials scientist at University College London: "There is the potential to cut the cost of titanium very substantially."

Related sites
Materials chemistry group at the University of Cambridge
For more about industrial applications of titanium