Ames Lab scientists experience ‘hard’ luck

Dustin Mcdonough

Scientists at the U.S. Department of Energy’s Ames Laboratory made an accidental discovery while experimenting with a material.

After adding a small amount of silicon to a combination of aluminum, magnesium and boron, they discovered the second-hardest substance known.

The hardest known substance is diamond.

“The discovery was really made on good luck,” said Alan Russell, associate scientist at Ames Lab and associate professor of materials science and engineering.

Bruce Cook, associate scientist at Ames Lab, made the discovery while working with thermoelectric materials.

“I was looking at some really complicated materials,” said Cook, lead investigator on the project. “I decided to follow the work that some people in Japan did a few years ago.”

He said he looked at a material known as aluminum magnesium boron and found that it was extremely hard.

“It was very difficult to cut with a precision diamond saw,” Cook explained.

“Anyone who has worked with a precision diamond saw knows that it can cut just about anything, but it wouldn’t cut this material,” he said.

The scientists worked with the material, researching its hardness.

By introducing silicon to the substance, it became slightly harder than cubic boron-nitride, which was the second-hardest material known before the discovery.

“It was a curious thing,” Russell said. “There was relatively little funding for the work, and we did it in our spare time. The whole thing was very serendipitous.”

He said the material discovered at Ames Lab would be used primarily for cutting and grinding steel products.

Diamond cannot be used on steel because when brought into contact with hot iron, it reacts by turning into graphite.

Cubic boron-nitride can be used for cutting and grinding steel, but it is very expensive to produce because it must be done under extreme conditions.

“Cubic boron-nitride has to be produced at temperatures in excess of 1,800 degrees C (3,272 degrees F) and pressures at 50,000 atmospheres,” Russell explained. “You can only produce a small amount of it at a time. That makes it more expensive than gold.”

The newly discovered material is less expensive, he said. Manufacturers could save a large amount of money by using it instead of cubic boron-nitride.

According to Russell, the substance also becomes harder when additives are introduced, something that usually does not happen.

The researchers sent samples of the material to a Michigan company that manufactures tools and molds for the automotive industry. Cook said the people there think the material will work well.

“That’s very encouraging for us,” he said.

Russell said the researchers at Ames Lab have known about the discovery for many months but waited to make the announcement until they were sure it would work.

“Whenever you have a material that flaunts the rules, it’s very peculiar,” he said. “We kept doubting ourselves.”

The researchers did a number of tests before announcing the discovery.

Together with Joel Harringa, assistant scientist at Ames Lab, Cook and Russell have submitted a paper on their findings to a peer-reviewed materials journal and have applied for a patent on the substance.

The scientists currently are looking for more funding and industrial partners to help them continue the research.

“We’ve barely begun to explore the possibilities of introducing additives to the substance,” Russell said.

The researchers also will investigate the possibility of liquefying the material and applying it as a wear-resistant coating on surfaces such as bulldozer and snowplow blades.

Cook and Russell both called the new discovery intriguing.

“It’s exciting when you see an entirely new frontier like this,” Russell said.