Scientists Create Sheets of Diamond From Graphite : Australia: The new carbon has many electronic and industrial applications, its inventors say.

SYDNEY, Australia —  Australian scientists have found a new way to make cheap diamonds: by blasting the soft gray graphite of pencils with an electric welder’s arc.

Amorphous diamonds, a new type of carbon identified by University of Sydney researchers, have many of the properties of natural diamonds and are cheap and thin enough to be used in the electronic circuitry of computers, scientists say.

The diamonds could also be used to make ball bearings that never wear out, computer chips that survive in extreme heat, scratch-resistant lenses and razor blades that don’t dull.

By stripping carbon atoms off graphite with a low-voltage electric arc and filtering the residue through a magnetic field, the Australians found that they could compress a carbon layer onto a substrate such as glass, plastic or ceramic.

This produces thin sheets of artificial diamond that are purer and cheaper than those made with conventional methods, according to the university’s David McKenzie and Bernard Pailthorpe.

The sheets are only 500 atoms thick, or 20 times thinner than the silicon chips that now carry computer circuitry.

Diamond, the hardest substance known, is also a superb electrical insulator. Scientists estimate that a diamond microchip could pack 1 billion transistors in a half-inch wafer, compared with 16 million in the most advanced microchip.

McKenzie and Pailthorpe say that, using supercomputers, they understand better how their sheets of “glassy” diamond are made.

This may have stolen them a lead in fine-tuning their methods for eventual application.

Pailthorpe said in a statement that the method could allow diamond film, expensive to produce and made in small amounts today, to go into large-scale production within a few years.

The Australian team, working with Britain’s University of Cambridge, has also successfully implanted working diamond diodes on a silicon chip.

“People have been trying to make diamond from graphite for ages, because they know that both are just different types of carbon,” Pailthorpe said.

In April, scientists in the United States detailed ways to use high-powered pulsed ultraviolet lasers to shear carbon atoms from graphite and deposit a thin diamond layer on a copper base.

Pailthorpe said that although the lasers produced the densest and purest artificial diamonds, it requires particle accelerators worth tens of millions of dollars and may prove too expensive to be used commercially.

The Australians use a technique called Vacuum Arc Deposition, using the electric and magnetic field filter.

It was developed by Soviet scientists in 1978 and is now being applied in hardening tools.

Commercial methods have since the late 1950s produced tiny, gritty diamonds by subjecting graphite to extreme pressures, but the process is extremely expensive.

It is used to harden tools and to protect camera lenses in space.

A new method, Chemical Vapor Deposition, has allowed large sheets of diamond film to be made.

But the sheets, per diamond carat, are more expensive than those made under the standard high-pressure technique.

Also, the chemical vapor-made diamond film is 300 times thicker than that produced by the Australian method.

The method produces crystalline diamond with a density equal to natural diamond, as does the pressure method.

Amorphous diamond made by the Australian group is more “glassy” but in many ways more useful.