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13.01.2016 | Ausgabe 4/2016

Metallurgical and Materials Transactions A 4/2016

RETRACTED ARTICLE: Fundamental Discovery of New Phases and Direct Conversion of Carbon into Diamond and hBN into cBN and Properties

Zeitschrift:
Metallurgical and Materials Transactions A > Ausgabe 4/2016
Autoren:
Jagdish Narayan, Anagh Bhaumik
Wichtige Hinweise
Manuscript submitted November 9, 2015.
Jagdish Narayan is the John C. C. Fan Family Distinguished University Professor in the Department of Materials Science and Engineering at North Carolina State University. After graduating with a B. Tech. (Distinction and First Rank) from IIT, Kanpur, in 1969, Narayan established an extraordinary academic record at the University of California, Berkeley, by finishing M.S. (1970) and Ph.D. (1971) degrees in a record time of two years. His pioneering research on defects and diffusion and novel materials laid foundations for materials processing needed for systems ranging from nano to micro and macroscale. Narayan’s work has been cited over 21,500 times with an h-index of over 72, and he has published nine books and more than 500 papers in scholarly journals. His honors include the 2014 North Carolina Science (highest civilian honor of the state of North Carolina) Award, the O. Max Gardner Award (highest UNC System honor), Holladay Medal and R.J. Reynolds Prize (North Carolina State’s highest honors for excellence in research, teaching, and extension), Acta Materialia Gold Medal and Prize given for pioneering contributions and leadership in materials science worldwide, ASM Gold Medal, TMS RF Mehl Gold Medal, U.S. Department of Energy Outstanding Research Award, and three IR-100 awards in addition to Fellow Honors from two academies and seven professional societies. Professor Narayan’s research has been duly recognized by the American Institute of Physics (AIP) in this year’s Nobel Prize in Physics on Blue Light Emitting Diodes (LEDs) made from Gallium Nitrides (III-nitrides) based materials. The AIP has singled out Narayan’s highly cited paper (J. Appl. Phys. 87, 965 (2000) with over 1,140 citations) on the development of GaN-based materials used in the Nobel Laureates’ work.
This article has been retracted by the Editor due to significant overlap with other publications by the same authors. Metallurgical and Materials Transactions policy does not allow for submission for publication of previously submitted or published work.
An erratum to this article can be found at http://​dx.​doi.​org/​10.​1007/​s11661-016-3566-8.

Abstract

We review the discovery of new phases of carbon (Q-carbon) and BN (Q-BN) and address critical issues related to direct conversion of carbon into diamond and hBN into cBN at ambient temperatures and pressures in air without any need for catalyst and the presence of hydrogen. The Q-carbon and Q-BN are formed as a result of quenching from super undercooled state by using high-power nanosecond laser pulses. We discuss the equilibrium phase diagram (PvsT) of carbon, and show that by rapid quenching, kinetics can shift thermodynamic graphite/diamond/liquid carbon triple point from 5000 K/12 GPa to super undercooled carbon at atmospheric pressure in air. Similarly, the hBN-cBN-Liquid triple point is shifted from 3500 K/9.5 GPa to as low as 2800 K and atmospheric pressure. It is shown that nanosecond laser heating of amorphous carbon and nanocrystalline BN on sapphire, glass, and polymer substrates can be confined to melt in a super undercooled state. By quenching this super undercooled state, we have created a new state of carbon (Q-carbon) and BN (Q-BN) from which nanocrystals, microcrystals, nanoneedles, microneedles, and thin films are formed depending upon the nucleation and growth times allowed and the presence of growth template. The large-area epitaxial diamond and cBN films are formed, when appropriate planar matching or lattice matching template is provided for growth from super undercooled liquid. The Q-phases have unique atomic structure and bonding characteristics as determined by high-resolution SEM and backscatter diffraction, HRTEM, STEM-Z, EELS, and Raman spectroscopy, and exhibit new and improved mechanical hardness, electrical conductivity, and chemical and physical properties, including room-temperature ferromagnetism and enhanced field emission. The Q-carbon exhibits robust bulk ferromagnetism with estimated Curie temperature of about 500 K and saturation magnetization value of 20 emu g−1. We have also deposited diamond on cBN by using a novel pulsed laser evaporation of carbon and obtained cBN/diamond composites, where cBN acts as template for diamond growth. Both diamond and cBN grown from super undercooled liquid can be alloyed with both p- and n-type dopants. This process allows carbon to diamond and hBN to cBN conversions and formation of useful nanostructures and microstructures at ambient temperatures in air at atmospheric pressure on practical and heat-sensitive substrates in a controlled way without need for any catalysts and hydrogen to stabilize sp3 bonding for diamond and cBN phases.

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