EPR-Characterization of Carbon Inclusions in Boron Carbide

• Published in: Journal of the American Ceramic Society 2004-07, Vol.87 (7), p.1336-1338
• Main Authors: Kakazey, Mykola, Vlasova, Maryna, Gonzalez-Rodriguez, Jose Gonzalo, Dominguez-Patiño, Martha, Leder, Ron
• Format: Article
• Language: English
• Subjects: boron carbide; Carbon; Condensed matter: electronic structure, electrical, magnetic, and optical properties; Condensed matter: structure, mechanical and thermal properties; Defects and impurities in crystals; microstructure; Electron paramagnetic resonance and relaxation; Exact sciences and technology; Indirect evidence of dislocations and other defects (resistivity, slip, creep, strains, internal friction, epr, nmr, etc.); Magnetic resonances and relaxations in condensed matter, mössbauer effect; Other ions and impurities; Oxidation; Physics; Sintering; Structure of solids and liquids; crystallography; Temperature; X-rays
• ISSN: 0002-7820; 1551-2916
• DOI: 10.1111/j.1151-2916.2004.tb07731.x

In boron carbide, the dependence of EPR line width (ΔB) with g= 2.0028 on the contents of free carbon, cC, is used to determine the surface‐to‐volume ratio (S/V) of free carbon inclusions. Consecutive reduction of cC was conducted by a method of low‐vacuum oxidation at a range of temperatures. The amount of a free carbon (a graphite phase) in samples was measured by X‐ray. Analysis of changes in ΔB (cC) has shown that free carbon inclusions at the surface layer of polycrystalline boron carbide particles has S/V two times smaller than that of free carbon inclusions in the interior of polycrystalline boron carbide.