Raman spectra of hot-pressed boron suboxide

¹DST/NRF Centre of Excellence in Strong Materials, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, South Africa

²School of Chemical and Metallurgical Engineering, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, South Africa

³CSIR National Laser Centre, P.O. Box 395, Pretoria 0001, South Africa

⁴Department of Physics and Biochemical Sciences University of Malawi, The Polytechnic Private Bag 303, Chichiri, Blantyre 0003 Malawi

⁵CSIR National Centre for Nano-Structured Materials, P.O. Box 395, Pretoria 0001, South Africa

⁶School of Physics, University of the Witwatersrand, Private Bag 3, Wits, Johannesburg 2050, South Africa

Adv. Mater. Lett., 2012, 2 (1), pp 58-64

DOI: 10.5185/amlett.2010.9167

Publication Date (Web): Apr 08, 2012

Copyright © IAAM-VBRI Press

E-mail: ronald.machaka@wits.ac.za

Abstract

Despite hot pressing being the most popular method of consolidating B₆O powder, the Raman spectrum of polycrystalline hot-pressed B₆O was until now poorly understood. Yet, recent reports have contributed to the understanding of only high-pressure and high-temperature sintered B₆O. Using an automated method for subtraction of the fluorescence background from Raman measurements, the first- and second-order Raman spectra of B₆O and their dependence on the wavelength of the excitation line from a green Argon ion (Ar⁺) laser are reported. Our results confirm the existence of observable highly resolved first- and second-order Raman modes measured at ambient conditions using a green Ar⁺ ion laser as the source of excitation. We also extend our study to present a comparative analysis of our recovered first-order Raman spectra and previously reported first-order Raman spectra other α-rhombohedral boron type based ultra-hard boron-rich ceramic materials. The results show an overall good agreement.

Keywords

Hot-pressed boron suboxide, B₆O, Raman spectroscopy, fluorescence background subtraction