title: Ultrahard stitching of nanotwinned diamond and cubic boron nitride in C2-BN composite.
abstract: Materials combining the hardness and strength of diamond with the higher thermal stability of cubic boron nitride (cBN) have broad potential value in science and engineering. Reacting nanodiamond with cBN at moderate pressures and high temperatures provides a pathway to such materials. Here we report the fabrication of Cx-BN nanocomposites, measuring up to 10 mm in longest dimension, by reacting nanodiamond with pre-synthesized cBN in a large-volume press. The nanocomposites consist of randomly-oriented diamond and cBN domains stitched together by sp(3)-hybridized C-B and C-N bonds, leading to p-type semiconductivity. Dislocations near the sutures accommodate lattice mismatch between diamond and cBN. Nanotwinning within both diamond and cBN domains further contributes to a bulk hardness ~50% higher than sintered cBN. The nanocomposite of C2-BN exhibits p-type semiconductivity with low activation energy and high thermal stability, making it a functional, ultrahard substance.
authors.affiliation: Department of Earth and Planetary Sciences, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Xiaobing
authors.initials: X
authors.lastname: Liu
authors.affiliation: Department of Earth and Planetary Sciences, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Xin
authors.initials: X
authors.lastname: Chen
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University, Changchun, Jilin 130012, China.
authors.forename: Hong-An
authors.initials: HA
authors.lastname: Ma
authors.affiliation: State Key Laboratory of Superhard Materials, Jilin University, Changchun, Jilin 130012, China.
authors.forename: Xiaopeng
authors.initials: X
authors.lastname: Jia
authors.affiliation: Northwestern University Atomic and Nanoscale Characterization Experimental (NUANCE) center, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Jinsong
authors.initials: J
authors.lastname: Wu
authors.affiliation: Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60439, USA.
authors.forename: Tony
authors.initials: T
authors.lastname: Yu
authors.affiliation: Center for Advanced Radiation Sources, University of Chicago, Chicago, Illinois 60439, USA.
authors.forename: Yanbin
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Physics &Astronomy, Rice University, Houston, Texas 77005-1827, USA.
authors.forename: Jiangang
authors.initials: J
authors.lastname: Guo
authors.affiliation: Bayerisches Geoinstitut, University of Bayreuth, Bayreuth 95444, Germany.
authors.forename: Sylvain
authors.initials: S
authors.lastname: Petitgirard
authors.affiliation: Department of Earth and Planetary Sciences, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Craig R
authors.initials: CR
authors.lastname: Bina
authors.affiliation: Department of Earth and Planetary Sciences, Northwestern University, Evanston, Illinois 60208, USA.
authors.forename: Steven D
authors.initials: SD
authors.lastname: Jacobsen