Maria Gilbert | Technische Universität Bergakademie Freiberg (original) (raw)

Papers by Maria Gilbert

Research paper thumbnail of Combined Diffusion Barrier and Wear-Resistant Thermal Spray Coatings on Light-Weight Charging Racks in Furnace Applications

International Thermal Spray Conference

Due to its low weight and excellent dimensional stability, carbon fibre-reinforced carbon (C/C) g... more Due to its low weight and excellent dimensional stability, carbon fibre-reinforced carbon (C/C) gains more and more importance as construction material for light-weight charging racks in industrial furnaces. However, for high-temperature applications above 1,000 °C, C/C has to be protected with a diffusion-inhibiting coating in order to avoid an undesired carburization of components which are in contact with the charging rack. In the present work, coatings were produced by means of atmospheric plasma spraying (APS) and powder flame spraying (PFS). The ceramic powders Al2O3, Al2O3/Cr2O3, Al2O3/TiO2 and yttria stabilized zirconia (YSZ) were used as coating materials, while molybdenum and silicon carbide served as adhesion-promoting intermediate layers. In order to reduce the residual stresses in the ceramic coatings, specimens with a defined segmented surface structure were compared with conventional closed coatings. Long-term high-temperature tests in several atmospheres were conduct...

Research paper thumbnail of Anforderungen biogener Brennstoffe an das Werkstoffkonzept zyklisch betriebener Kleinfeuerungsanlagen

Keramische Zeitschrift, 2019

Hersteller von Kleinfeuerungsanlagen sind aktuell gefordert, ihre werkstoffkonzepte an die zunehm... more Hersteller von Kleinfeuerungsanlagen sind aktuell gefordert, ihre werkstoffkonzepte an die zunehmende Variabilität der Brennstoffe anzupassen. Die Durchführung von Auslagerungsversuchen hitze-und zunderbeständiger Stähle und Feuerbetone in Rauchgasen aus der Miscanthusverbrennung sowie adaptierte K 2 CO 3-Tiegeltests lassen erste Rückschlüsse auf die Beständigkeit der untersuchten Materialien in Verbrennungsgasen aus biogenen Brennstoffen zu. Thermodynamische Berechnungen ermöglichen eine Abschätzung der vorliegenden Partialdrücke korrosiver Verbindungen in Verbrennungsanlagen.

Research paper thumbnail of Thermally sprayed diffusion barrier coatings on C/C light-weight charging racks for furnace applications

Surface and Coatings Technology, 2013

Charging racks are used for the positioning and transport of workpieces in heat treatment and hig... more Charging racks are used for the positioning and transport of workpieces in heat treatment and hightemperature brazing processes. Conventionally, they are made of steel or cast iron, but in recent years, more and more companies have changed over to charging racks made of lightweight materials such as graphite or carbon fiber-reinforced carbon (C/C). However, the main problem of these carbon-based workpiece carriers is the undesired carburization of components, which are in contact with the rack, by means of diffusion processes. For that reason, within the scope of the presented work, thermally sprayed coatings were applied on C/C and extensively tested for their suitability as high-temperature diffusion barrier. The ceramic powders Al 2 O 3 , Al 2 O 3 /Cr 2 O 3 , Al 2 O 3 /TiO 2 and ZrO 2 /Y 2 O 3 were chosen as coating materials and processed by powder flame spraying (PFS) and atmospheric plasma spraying (APS). Molybdenum and silicon carbide served as adhesion-promoting intermediate layers. Coating characterization included materialographic analyses, tensile strength and tribometric tests as well as long-term high-temperature tests, both laboratoryscaled and in industrial practice. Especially Al 2 O 3 and Al 2 O 3 /Cr 2 O 3 coatings on siliconized C/C exhibited excellent results, proving the wide application potential of thermally sprayed ceramic coatings on carbon-based lightweight materials.

Research paper thumbnail of Tribologische Betrachtung moderner Chargiergestelle*

HTM Journal of Heat Treatment and Materials, 2012

Kurzfassung Bei der Beschickung von Chargiergestellen sowie deren Gebrauch in Wärmebehandlungsanl... more Kurzfassung Bei der Beschickung von Chargiergestellen sowie deren Gebrauch in Wärmebehandlungsanlagen kommt es zu Relativbewegungen zwischen dem Gestell und dem behandelten Gut. Verhindern die im System wirkenden Haftreibungskräfte Gleitvorgänge, kann es bei hohen Temperaturen zu Bauteilverzug kommen. Die Auswirkungen einer Substitution herkömmlicher Edelstahlgussgestelle durch Gestelle auf Kohlenstoffbasis werden aus tribologischer Sicht untersucht. Während Metallpaarungen bei Temperaturen über 600 °C einen starken Anstieg der Reibwerte zeigen, werden oberhalb der genannten Temperatur bei den Tribosystemen 100Cr6/CFC und 100Cr6/Graphit niedrigere Reibwerte um 0,4 ermittelt. Alle bisherigen Ergebnisse lassen darauf schließen, dass der Ersatz herkömmlicher Stahlgestelle durch CFC-Gestelle nicht nur im Hinblick auf Festigkeit, Thermoschockbeständigkeit, Erwärm-/Abkühldauern und Transportaufwand Vorteile bringt, sondern auch der Gefahr des Verzuges behandelter Bauteile entgegenwirkt.

Research paper thumbnail of Combined Diffusion Barrier and Wear-Resistant Thermal Spray Coatings on Light-Weight Charging Racks in Furnace Applications

International Thermal Spray Conference

Due to its low weight and excellent dimensional stability, carbon fibre-reinforced carbon (C/C) g... more Due to its low weight and excellent dimensional stability, carbon fibre-reinforced carbon (C/C) gains more and more importance as construction material for light-weight charging racks in industrial furnaces. However, for high-temperature applications above 1,000 °C, C/C has to be protected with a diffusion-inhibiting coating in order to avoid an undesired carburization of components which are in contact with the charging rack. In the present work, coatings were produced by means of atmospheric plasma spraying (APS) and powder flame spraying (PFS). The ceramic powders Al2O3, Al2O3/Cr2O3, Al2O3/TiO2 and yttria stabilized zirconia (YSZ) were used as coating materials, while molybdenum and silicon carbide served as adhesion-promoting intermediate layers. In order to reduce the residual stresses in the ceramic coatings, specimens with a defined segmented surface structure were compared with conventional closed coatings. Long-term high-temperature tests in several atmospheres were conduct...

Research paper thumbnail of Anforderungen biogener Brennstoffe an das Werkstoffkonzept zyklisch betriebener Kleinfeuerungsanlagen

Keramische Zeitschrift, 2019

Hersteller von Kleinfeuerungsanlagen sind aktuell gefordert, ihre werkstoffkonzepte an die zunehm... more Hersteller von Kleinfeuerungsanlagen sind aktuell gefordert, ihre werkstoffkonzepte an die zunehmende Variabilität der Brennstoffe anzupassen. Die Durchführung von Auslagerungsversuchen hitze-und zunderbeständiger Stähle und Feuerbetone in Rauchgasen aus der Miscanthusverbrennung sowie adaptierte K 2 CO 3-Tiegeltests lassen erste Rückschlüsse auf die Beständigkeit der untersuchten Materialien in Verbrennungsgasen aus biogenen Brennstoffen zu. Thermodynamische Berechnungen ermöglichen eine Abschätzung der vorliegenden Partialdrücke korrosiver Verbindungen in Verbrennungsanlagen.

Research paper thumbnail of Thermally sprayed diffusion barrier coatings on C/C light-weight charging racks for furnace applications

Surface and Coatings Technology, 2013

Charging racks are used for the positioning and transport of workpieces in heat treatment and hig... more Charging racks are used for the positioning and transport of workpieces in heat treatment and hightemperature brazing processes. Conventionally, they are made of steel or cast iron, but in recent years, more and more companies have changed over to charging racks made of lightweight materials such as graphite or carbon fiber-reinforced carbon (C/C). However, the main problem of these carbon-based workpiece carriers is the undesired carburization of components, which are in contact with the rack, by means of diffusion processes. For that reason, within the scope of the presented work, thermally sprayed coatings were applied on C/C and extensively tested for their suitability as high-temperature diffusion barrier. The ceramic powders Al 2 O 3 , Al 2 O 3 /Cr 2 O 3 , Al 2 O 3 /TiO 2 and ZrO 2 /Y 2 O 3 were chosen as coating materials and processed by powder flame spraying (PFS) and atmospheric plasma spraying (APS). Molybdenum and silicon carbide served as adhesion-promoting intermediate layers. Coating characterization included materialographic analyses, tensile strength and tribometric tests as well as long-term high-temperature tests, both laboratoryscaled and in industrial practice. Especially Al 2 O 3 and Al 2 O 3 /Cr 2 O 3 coatings on siliconized C/C exhibited excellent results, proving the wide application potential of thermally sprayed ceramic coatings on carbon-based lightweight materials.

Research paper thumbnail of Tribologische Betrachtung moderner Chargiergestelle*

HTM Journal of Heat Treatment and Materials, 2012

Kurzfassung Bei der Beschickung von Chargiergestellen sowie deren Gebrauch in Wärmebehandlungsanl... more Kurzfassung Bei der Beschickung von Chargiergestellen sowie deren Gebrauch in Wärmebehandlungsanlagen kommt es zu Relativbewegungen zwischen dem Gestell und dem behandelten Gut. Verhindern die im System wirkenden Haftreibungskräfte Gleitvorgänge, kann es bei hohen Temperaturen zu Bauteilverzug kommen. Die Auswirkungen einer Substitution herkömmlicher Edelstahlgussgestelle durch Gestelle auf Kohlenstoffbasis werden aus tribologischer Sicht untersucht. Während Metallpaarungen bei Temperaturen über 600 °C einen starken Anstieg der Reibwerte zeigen, werden oberhalb der genannten Temperatur bei den Tribosystemen 100Cr6/CFC und 100Cr6/Graphit niedrigere Reibwerte um 0,4 ermittelt. Alle bisherigen Ergebnisse lassen darauf schließen, dass der Ersatz herkömmlicher Stahlgestelle durch CFC-Gestelle nicht nur im Hinblick auf Festigkeit, Thermoschockbeständigkeit, Erwärm-/Abkühldauern und Transportaufwand Vorteile bringt, sondern auch der Gefahr des Verzuges behandelter Bauteile entgegenwirkt.