In collaboration with Dr. Laura Silvestroni, member of the National Reseach Council of Italy Institute of Science and Technology for Ceramics (CNR-ISTEC Faenza, Italy), a microstructure evolution study of a 15 vol.% MoSi2-doped ZrB2 ceramic, provided by CNR-ISTEC, as-sintered and upon oxidation at 1650 and 1800°C for 15 min was performed. Scanning- and transmission electron microscopy enabled disclose microstructural features occurred during oxidation never observed before.In the pristine material, (Zr,Mo)B2 solid solutions surround the original ZrB2 nuclei. After oxidation at 1650°C and 1800°C, the microstructure is characterized by intragranular nanostructures, in which nanosized MoB inclusions remained trapped within ZrO2 grains, or decorate their surfaces.However, the sample that underwent oxidation at 1800°C is characterized by the formation of columnar ZrO2, followed by a glassy layer of silica intermixed with ZrO2, indicating a massive change in oxidation kinetics. Moreover enhanced diffusion of oxygen inside the sample resulted in severely enhanced surface oxidation.

Electron Microscopy Studies on the Oxidation Resistance of ZrB2/MoSi2 Composites / Stricker, Kerstin; Silvestroni, Laura. - (2017).

Electron Microscopy Studies on the Oxidation Resistance of ZrB2/MoSi2 Composites

Laura Silvestroni
2017

Abstract

In collaboration with Dr. Laura Silvestroni, member of the National Reseach Council of Italy Institute of Science and Technology for Ceramics (CNR-ISTEC Faenza, Italy), a microstructure evolution study of a 15 vol.% MoSi2-doped ZrB2 ceramic, provided by CNR-ISTEC, as-sintered and upon oxidation at 1650 and 1800°C for 15 min was performed. Scanning- and transmission electron microscopy enabled disclose microstructural features occurred during oxidation never observed before.In the pristine material, (Zr,Mo)B2 solid solutions surround the original ZrB2 nuclei. After oxidation at 1650°C and 1800°C, the microstructure is characterized by intragranular nanostructures, in which nanosized MoB inclusions remained trapped within ZrO2 grains, or decorate their surfaces.However, the sample that underwent oxidation at 1800°C is characterized by the formation of columnar ZrO2, followed by a glassy layer of silica intermixed with ZrO2, indicating a massive change in oxidation kinetics. Moreover enhanced diffusion of oxygen inside the sample resulted in severely enhanced surface oxidation.
2017
Istituto di Scienza, Tecnologia e Sostenibilità per lo Sviluppo dei Materiali Ceramici - ISSMC (ex ISTEC)
transmission electron microscopy
microstructure
oxidation
borides
Laura Silvestroni, Hans-Joachim Kleebe
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.14243/443879
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