Next Article in Journal
Al2O3 Coatings on Magnesium Alloy Deposited by the Fluidized Bed (FB) Technique
Next Article in Special Issue
Thermal Properties of SiOC Glasses and Glass Ceramics at Elevated Temperatures
Previous Article in Journal
Flexural Behavior of GFRP Tubes Filled with Magnetically Driven Concrete
Previous Article in Special Issue
Synthesis of a Novel Polyethoxysilsesquiazane and Thermal Conversion into Ternary Silicon Oxynitride Ceramics with Enhanced Thermal Stability
Article Menu
Issue 1 (January) cover image

Export Article

Open AccessFeature PaperArticle
Materials 2018, 11(1), 93; https://doi.org/10.3390/ma11010093

High-Temperature Raman Spectroscopy of Nano-Crystalline Carbon in Silicon Oxycarbide

Institut für Material- und Geowissenschaften, Technische Universität Darmstadt, Otto-Berndt-Straße 3, 64287 Darmstadt, Germany
*
Author to whom correspondence should be addressed.
Received: 5 December 2017 / Revised: 26 December 2017 / Accepted: 5 January 2018 / Published: 9 January 2018
(This article belongs to the Special Issue Polymer Derived Ceramics and Applications)
View Full-Text   |   Download PDF [2603 KB, uploaded 9 January 2018]   |  

Abstract

The microstructure of segregated carbon in silicon oxycarbide (SiOC), hot-pressed at T = 1600 °C and p = 50 MPa, has been investigated by VIS Raman spectroscopy (λ = 514 nm) within the temperature range 25–1000 °C in air. The occurrence of the G, D’ and D bands at 1590, 1620 and 1350 cm−1, together with a lateral crystal size La < 10 nm and an average distance between lattice defects LD ≈ 8 nm, provides evidence that carbon exists as nano-crystalline phase in SiOC containing 11 and 17 vol % carbon. Both samples show a linear red shift of the G band up to the highest temperature applied, which is in agreement with the description of the anharmonic contribution to the lattice potential by the modified Tersoff potential. The temperature coefficient χG = −0.024 ± 0.001 cm−1/°C is close to that of disordered carbon, e.g., carbon nanowalls or commercial activated graphite. The line width of the G band is independent of temperature with FWHM-values of 35 cm−1 (C-11) and 45 cm−1 (C-17), suggesting that scattering with defects and impurities outweighs the phonon-phonon and phonon-electron interactions. Analysis of the Raman line intensities indicates vacancies as dominating defects. View Full-Text
Keywords: polymer-derived ceramics; Raman spectroscopy; anharmonicity; carbon; defects polymer-derived ceramics; Raman spectroscopy; anharmonicity; carbon; defects
Figures

Figure 1

This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. (CC BY 4.0).
SciFeed

Share & Cite This Article

MDPI and ACS Style

Rosenburg, F.; Ionescu, E.; Nicoloso, N.; Riedel, R. High-Temperature Raman Spectroscopy of Nano-Crystalline Carbon in Silicon Oxycarbide. Materials 2018, 11, 93.

Show more citation formats Show less citations formats

Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.

Related Articles

Article Metrics

Article Access Statistics

1

Comments

[Return to top]
Materials EISSN 1996-1944 Published by MDPI AG, Basel, Switzerland RSS E-Mail Table of Contents Alert
Back to Top