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Negative Additive Manufacturing of Complex Shaped Boron Carbides
Published on: September 18, 2018
Advanced microstructure of boron carbide.
Helmut Werheit1, Sulkhan Shalamberidze
1Institute of Physics, University Duisburg-Essen, Duisburg, Germany. helmut.werheit@uni-duisburg-essen.de
Journal of Physics. Condensed Matter : an Institute of Physics Journal
|September 5, 2012
Summary
Boron carbide structures were analyzed using IR phonon spectroscopy. This revealed specific atomic arrangements and deviations from theoretical predictions, with silicon doping inducing isotope randomization.
Area of Science:
- Materials Science
- Solid-State Physics
- Spectroscopy
Background:
- Boron carbide (BₓC) exhibits complex rhombohedral structures.
- These structures consist of icosahedral units (B₁₂ or B₁₁C) and linear arrangements (CBC, CBB, B□B).
- The precise composition and arrangement vary within the homogeneity range.
Purpose of the Study:
- To quantitatively determine the concentrations of structural components in boron carbide.
- To investigate the actual structure of boron carbide compared to theoretical predictions.
- To understand the effect of isotopic composition and silicon doping on boron carbide structure.
Main Methods:
- Infrared (IR) phonon spectroscopy of isotopically pure boron carbide.
- Analysis of spectral data to deduce quantitative concentrations of structural units.
- Comparison of experimental findings with theoretical models.
Main Results:
- Quantitative concentrations of B₁₂ icosahedra, B₁₁C icosahedra, and CBC, CBB, B□B linear arrangements were determined.
- The structure of B₁₃C₂ deviates significantly from the theoretically predicted B₁₂CBC structure, being the most distorted.
- Natural boron carbide (BₓC) shows non-random boron isotope distribution.
- Doping with 2% silicon leads to a random distribution of boron isotopes.
Conclusions:
- IR phonon spectroscopy is effective for characterizing complex boron carbide structures.
- Experimental structures of boron carbide, particularly B₁₃C₂, differ from energetically favorable theoretical models.
- Isotopic distribution in boron carbide is sensitive to composition and external factors like silicon doping.
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