Researchers combine diamond and cubic boron nitride with a novel alloying process for a superhard material

September 8, 2015, American Institute of Physics
A and B show a bulk diamond-cBN alloy samples synthesized at 20 GPa/2200 °C with a diameter of ~3 mm, over a copper screen to exhibit its transparency C and D show polished rake faces of diamond-cBN alloy cutters. Credit: D. W. He/SCU

Diamonds are forever, except when they oxidize while cutting through iron, cobalt, nickel, chromium, or vanadium at high temperatures. Conversely, cubic boron nitride possesses superior chemical inertness but only about half of the hardness of diamonds. In an attempt to create a superhard material better suited for a wide variety of materials on an industrial scale, researchers at Sichuan University in Chengdu, China, have created an alloy composed of diamonds and cubic boron nitride (cBN) that boasts the benefits of both.

"Diamond and cubic boron nitride could readily form alloys that can potentially fill the performance gap because of their affinity in structure lattices and covalent bonding character," said Duanwei He, a professor at Sichauan University's Institute of Atomic and Molecular Physics. "However, the idea has never been demonstrated because samples obtained in previous studies are too small to test their practical performance."

He and his colleagues at the University of Nevada and the Chinese Academy of Sciences detail their procedure this week in Applied Physics Letters.

To synthesize diamond-cBN , the researchers subjected a homogenous mixture of diamond and cubic boron nitride powder to a vacuum furnace at 1300 K for two hours, then pressed the material into 3.5 millimeter pellets under pressure greater than 15 gigapascals and temperatures above 2000 K. The pellets were then polished and sharpened into cutting implements.

The researchers tested the cutting performances of their alloy on hardened steel and granite bars on a computer numerical controlled lathe. They found that the diamond-cBN alloy rivaled polycrystalline cubic 's wear and tool life on the steel samples, and exhibited significantly less wear when cutting through granite. The alloy also demonstrated a more preferable high-speed cutting performance than either polycrystalline CBN or commercial polycrystalline diamonds.

Future work for He and his colleagues involves developing synthesis technology for centimeter-sized diamond-cBN alloy bulks to bring the process up to industrial-scale production.

Explore further: Scientists come closer to the industrial synthesis of a material harder than diamond

More information: "Diamond-cBN Alloy: a Universal Cutting Method" by Pei Wang, Duanwei He, Liping Wang, Zili Kou, Yong Li, Lun Xiong, Qiwei Hu, Chao Xu, Li Lei, Qiming Wang, Jing Liu, and Yusheng Zhao. Applied Physics Letters , September 8, 2015. DOI: 10.1063/1.4929728

Related Stories

Science is harnessing shock waves to create new materials

August 13, 2013

(Phys.org) —Researchers at Purdue University are part of a national effort to develop new materials having super strength and other properties by using shock waves similar to those generated by meteorites striking the Earth.

For 2-D boron, it's all about that base

September 2, 2015

Rice University scientists have theoretically determined that the properties of atom-thick sheets of boron depend on where those atoms land.

Recommended for you

Scientists produce 3-D chemical maps of single bacteria

November 16, 2018

Scientists at the National Synchrotron Light Source II (NSLS-II)—a U.S. Department of Energy (DOE) Office of Science User Facility at DOE's Brookhaven National Laboratory—have used ultrabright x-rays to image single bacteria ...

Bursting bubbles launch bacteria from water to air

November 15, 2018

Wherever there's water, there's bound to be bubbles floating at the surface. From standing puddles, lakes, and streams, to swimming pools, hot tubs, public fountains, and toilets, bubbles are ubiquitous, indoors and out.

Terahertz laser pulses amplify optical phonons in solids

November 15, 2018

A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg/Germany presents evidence of the amplification of optical phonons ...

Quantum science turns social

November 15, 2018

Researchers in a lab at Aarhus University have developed a versatile remote gaming interface that allowed external experts as well as hundreds of citizen scientists all over the world to optimize a quantum gas experiment ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.