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MM: Fachverband Metall- und Materialphysik
MM 63: Functional Materials: Performance, Reliability and Degradation
MM 63.2: Vortrag
Donnerstag, 21. März 2024, 15:45–16:00, C 230
Structural and chemical behavior of cBN at high pressure and temperature — •Lars Olschewski1, Gabriel Brune1, Tountzer Dereli2, Monika Kipp2, Dirk Biermann2, and Jörg Debus1 — 1Department of Physics, TU Dortmund — 2Institute of Machining Technology, TU Dortmund
Solids need to withstand high temperatures and heavy forces while they are used in extreme thermo-mechanical environments, like high-speed precision-grinding applications. Cubic boron nitride (cBN) is commonly exploited as abrasive material, because it is structurally stable and resistant to oxidation typically until temperatures of 1300∘C.
For applying strong normal and tangential forces (tens of N) and high temperatures, the mechanically most stable (sp3-hybridized) cBN may change into its hexagonal form or its crystal structure may transform into an amorphous mixture of stressed and anisotropic sp2- and sp3-hybridized bonds. In that context, studying the anisotropies in the tensile, compressive and shear strain as well as surficial chemical reaction products is highly interesting.
This structural and chemical behavior is investigated by confocal Raman scattering and tip-enhanced Raman spectroscopy. They allow for sensitively characterizing topographic features at the nanoscale combined with data on, e.g., the chemical composition.
Keywords: cBN; TERS; abrasive grains; thermomechanical properties; Raman spectroscopy