Osmium diboride, an ultra-incompressible, hard material.
The need for wear- and scratch-resistant materials drives the quest for new superhard materials. In this work, we apply two design parameters to identify ultra-incompressible, superhard materials-high valence electron density and high bond covalency. Our first example of such a material is OsB2. The bulk modulus of OsB2 was measured using in situ high-pressure X-ray diffraction and was determined to be in the range of 365-395 GPa. While this value is slightly less than that of the bulk modulus of diamond, due to the anisotropic crystal structure of OsB2, the axis compressibility in the orthorhombic c-direction is less than the axis compressibility found in diamond. OsB2 also scratches the surface of a sapphire window, indicating that the hardness of OsB2 exceeds 2000 kg/mm2.
Cumberland
Robert W
RW
Department of Chemistry and Biochemistry, University of California, Los Angeles, 90095-1569, USA.
Weinberger
Michelle B
MB
Gilman
John J
JJ
Clark
Simon M
SM
Tolbert
Sarah H
SH
Kaner
Richard B
RB