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Title: Synthesis of Ultra-Incompressible Superhard Rhenium Diboride at Ambient Pressure

Abstract

The quest to create superhard materials rarely strays from the use of high-pressure synthetic methods, which typically require gigapascals of applied pressure. We report that rhenium diboride (ReB{sub 2}), synthesized in bulk quantities via arc-melting under ambient pressure, rivals materials produced with high-pressure methods. Microindentation measurements on ReB{sub 2} indicated an average hardness of 48 gigapascals under an applied load of 0.49 newton, and scratch marks left on a diamond surface confirmed its superhard nature. Its incompressibility along the c axis was equal in magnitude to the linear incompressibility of diamond. In situ high-pressure x-ray diffraction measurements yielded a bulk modulus of 360 gigapascals, and radial diffraction indicated that ReB{sub 2} is able to support a remarkably high differential stress. This combination of properties suggests that this material may find applications in cutting when the formation of carbides prevents the use of traditional materials such as diamond.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Laboratory (BNL) National Synchrotron Light Source
Sponsoring Org.:
Doe - Office Of Science
OSTI Identifier:
930663
Report Number(s):
BNL-81156-2008-JA
Journal ID: ISSN 0193-4511; SCEHDK; TRN: US200901%%21
DOE Contract Number:
DE-AC02-98CH10886
Resource Type:
Journal Article
Resource Relation:
Journal Name: Science; Journal Volume: 316
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; RHENIUM BORIDES; HARDNESS; SYNTHESIS; COMPRESSIBILITY; ATMOSPHERIC PRESSURE; CUTTING TOOLS; national synchrotron light source

Citation Formats

Chung,H., Weinberger, M., Levine, J., Kavner, A., Yang, J., Tolbert, S., and Kaner, R.. Synthesis of Ultra-Incompressible Superhard Rhenium Diboride at Ambient Pressure. United States: N. p., 2007. Web. doi:10.1126/science.1139322.
Chung,H., Weinberger, M., Levine, J., Kavner, A., Yang, J., Tolbert, S., & Kaner, R.. Synthesis of Ultra-Incompressible Superhard Rhenium Diboride at Ambient Pressure. United States. doi:10.1126/science.1139322.
Chung,H., Weinberger, M., Levine, J., Kavner, A., Yang, J., Tolbert, S., and Kaner, R.. Mon . "Synthesis of Ultra-Incompressible Superhard Rhenium Diboride at Ambient Pressure". United States. doi:10.1126/science.1139322.
@article{osti_930663,
title = {Synthesis of Ultra-Incompressible Superhard Rhenium Diboride at Ambient Pressure},
author = {Chung,H. and Weinberger, M. and Levine, J. and Kavner, A. and Yang, J. and Tolbert, S. and Kaner, R.},
abstractNote = {The quest to create superhard materials rarely strays from the use of high-pressure synthetic methods, which typically require gigapascals of applied pressure. We report that rhenium diboride (ReB{sub 2}), synthesized in bulk quantities via arc-melting under ambient pressure, rivals materials produced with high-pressure methods. Microindentation measurements on ReB{sub 2} indicated an average hardness of 48 gigapascals under an applied load of 0.49 newton, and scratch marks left on a diamond surface confirmed its superhard nature. Its incompressibility along the c axis was equal in magnitude to the linear incompressibility of diamond. In situ high-pressure x-ray diffraction measurements yielded a bulk modulus of 360 gigapascals, and radial diffraction indicated that ReB{sub 2} is able to support a remarkably high differential stress. This combination of properties suggests that this material may find applications in cutting when the formation of carbides prevents the use of traditional materials such as diamond.},
doi = {10.1126/science.1139322},
journal = {Science},
number = ,
volume = 316,
place = {United States},
year = {Mon Jan 01 00:00:00 EST 2007},
month = {Mon Jan 01 00:00:00 EST 2007}
}
  • Lattice vibrational properties of superhard rhenium diboride (ReB{sub 2}) were examined up to 8 GPa in a diamond anvil cell using Raman spectroscopy techniques. Linear pressure coefficients and mode Grüneisen parameters are obtained. Good agreement is found between the experimental and theoretical calculated Grüneisen parameters. Examination of the calculated mode Grüneisen parameters reveals that both B-B and Re-B covalent bonds play a dominant role in supporting the applied load under pressure. A comparison of vibrations parallel and perpendicular to the c-axis indicates that bonds along the c-axis tend to take greater loads. Our results agree with observations of elastic lattice anisotropymore » obtained from both in situ X-ray diffraction measurements and ultrasonic resonance spectra.« less
  • The elastic moduli of polycrystalline rhenium diboride are measured as a function of temperature between 5 and 325 K. The room temperature results show that ReB{sub 2} has very high values for both the bulk and shear modulus, confirming the incompressible and superhard nature of this material. With decreasing temperature, the moduli increase, with a hint of softening below 50 K.
  • No abstract prepared.
  • We report on a comprehensive study of thermodynamic and mechanical properties as well as a bond-deformation mechanism on ultra-incompressible Re{sub 2} N and Re{sub 3} N. The introduction of nitrogen into the rhenium lattice leads to thermodynamic instability in Re{sub 2} N at ambient conditions and enhanced incompressibility and strength for both rhenium nitrides. Rhenium nitrides, however, show substantially lower ideal shear strength than hard ReB{sub 2} and superhard c -BN, suggesting that they cannot be intrinsically superhard. An intriguing soft “ionic bond mediated plastic deformation” mechanism is revealed to underline the physical origin of their unusual mechanical strength. Thesemore » results suggest a need to reformulate the design concept of intrinsically superhard transition-metal nitrides, borides, and carbides.« less