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Lecture

(Thermo)Mechanical Properties of SiOC-Based Glasses and Glass Ceramics

Thursday (29.09.2016)
16:15 - 16:30
Part of:


In the present study, dense monolithic SiOC glasses and glass ceramics with different compositions (i.e., various carbon contents) and different microstructures (i.e., single-phasic and phase-separated) were prepared and structurally characterized.

The high-temperature creep behavior of the investigated glasses was assessed and revealed two features of the studied SiOC samples: (i) a viscous contribution to the creep, coming from the silica rich network, and (ii) an elastic response to stress, coming from the segregated carbon phase present in the samples; this is in agreement to the previously proposed nano-heterogeneous network topology of SiOC glasses.

Furthermore, two distinct effects of the carbon phase on the HT creep behavior of SiOC were identified and will be discussed: the effect of the carbon present within the SiOC network (the "carbidic" carbon), which induces a significant increase of the viscosity and a strong decrease of the activation energy for creep as compared to vitreous silica; and the influence of the segregated carbon phase, which has been shown to affect the viscosity and the activation energy of creep and dominates the creep behavior in phase-separated silicon oxycarbides.

In addition to the effect of the phase composition and microstructure on the high-temperature creep behavior of SiOC glasses and glass ceramics, studies related to their elastic properties (Young's modulus, Poisson ratio), hardness as well as thermal conductivity will be presented and discussed.

Speaker:
Christina Stabler
Darmstadt University of Technology
Additional Authors:
  • Prof. Dr. Martin Heilmaier
    Karlsruhe Institute of Technology
  • Prof. Dr. Lothar Wondraczek
    Friedrich-Schiller University Jena
  • Dr. Emanuel Ionescu
    Darmstadt University of Technology
  • Prof. Dr. Ralf Riedel
    Darmstadt University of Technology