TU Bergakademie Freiberg Data Publications

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Data publications from research of Freiberg University of Mining and Technology.

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Browsing TU Bergakademie Freiberg Data Publications by Subject "4::43"

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  • ItemPublic Metadata
    GRK 2802: HIGH-TEMPERATURE COMPRESSION TESTS AND ACCOMPANYING SEM INVESTIGATIONS OF MgO-C REFRACTORIES BASED ON FRESH MgO AND RECYCLATE
    (Technische Universität Bergakademie Freiberg, 2025-08-27) Schramm, Alexander; Weidner, Anja; Biermann, Horst; Stadtmüller, Till M. J.; Aneziris, Christos G.; Schemmel, Thomas
    With regard to the increasingly desired recycling of refractories, the properties of MgO-C containing recyclate are of high economic and ecological relevance. Two commercially available grades were studied to evaluate the influence of recyclate in MgO-C materials: MgO-C consisting only of fresh MgO as well as MgO-C with 50 wt.% recyclate. In this study, compression tests on these MgO-C materials were performed at room temperature, 1000°C and 1300°C. In order to investigate the microstructure and to identify the occurring damage mechanisms, scanning electron microscopy (SEM) investigations were carried out. The compression tests provided higher strengths at room temperature and at 1000°C for the MgO-C grade with recyclate compared to the grade with only fresh MgO and comparable strengths at 1300°C. Thus, the use of recycled agglomerates had no negative effect on the compressive strength.
  • ItemPublic Metadata
    GRK 2802: Hochtemperatur-Biegefestigkeit von kohlenstoffgebundenem Magnesiumoxid (MgO-C) unter Einbindung von DIC
    (Technische Universität Bergakademie Freiberg, 2025-09-16) Schramm, Alexander; Knöchel, Lukas; Biermann, Horst; Weidner, Anja
    Kohlenstoffgebundenes Magnesiumoxid (MgO-C) als Vertreter der Feuerfestwerkstoffe ist als Zustellungsmaterial in Konvertern, Stahlgießpfannen und Elektrolichtbogenöfen unverzichtbar. Der Werkstoff ist in der Anwendung komplexen thermischen, mechanischen und korrosiven Beanspruchungen ausgesetzt. Die Bewertung der quasi-statischen Hochtemperaturfestigkeit ist daher von zentralem Interesse und Gegenstand der vorliegenden Studie. Vier-Punkt-Biegeversuche an kommerziellem MgO-C Feuerfestmaterial wurden in einer Hochtemperaturprüfmaschine unter Schutzgas bis 1300°C durchgeführt. Mittels digitaler Bildkorrelation (DIC) bei Raumtemperatur wurden Aussagen zu ablaufenden Schädigungsmechanismen gemacht. Die in dieser Studie durchgeführten Versuche lieferten bei erhöhten Temperaturen höhere Biegefestigkeiten als bei Raumtemperatur, was auf das Schließen von Rissen entlang der Grenzfläche zwischen MgO und kohlenstoffhaltiger Matrix zurückgeführt wird.
  • ItemOpen Access
    Research Data - Determination of total hemispherical emissivity utilizing an in-situ calibrated, coupled experimental-simulative electron beam calorimetric approach
    (Technische Universität Bergakademie Freiberg, 2026-03-10) Kerber, Konrad
    The accurate determination of the total hemispherical emission coefficient (THEC) of materials is essential for modeling radiative heat transfer in high-temperature vacuum environments. This study presents a rapid steady-state calorimetric method to determine the THEC using a vacuum electron beam (EB) facility. A graphite-coated Inconel 718 foil with a thickness comparable to the electron penetration depth was used as the emission target, allowing temperature equalization within seconds. Surface temperatures were recorded via a calibrated two-colour thermal imaging system. An in-situ calibration was conducted, using the melting point of pure copper as a fixed reference. Numerical simulations were employed to validate both the emissivity determination and the temperature calibration methodology. EB heating efficiency was determined at 150 keV in a combined experimental-simulative approach using Monte Carlo simulations and backscattered electron intensity capture. Temperature calibration showed high reproducibility with a median absolute deviation of +- 0.4% and a half range of +- 1.1% at 1085 °C, and was shown to be transferable to other materials. EB heating efficiency slightly decreased from 0.832 +- 0.003 at room temperature to 0.825 +- 0.002 between 800 °C to 1140 °C. THEC values between 0.88 and 0.92 with a maximum half range of +-0.06 were obtained in the range of 840 °C to 1110 °C for graphite-coated Inconel 718 with a median roughness of Ra = 1.2 µm. Reflected radiation from the emission target and thermal losses from conduction and sublimation were assessed and found negligible. Results were consistent with literature, particularly under high surface roughness or pre-oxidized conditions.