Mechanical properties of polymer-derived ceramics are usually measured on samples pyrolyzed in inert atmosphere. Here, we report the hardness and elastic modulus of SiOC and SiCN pyrolyzed in both inert (Ar) and reactive (CO2) atmosphere. The external surface of the specimens exposed to the pyrolysis gas was characterized by Vickers microhardness measurements and infrared spectroscopy. The elastic modulus was evaluated by three-point bending tests on thin (150-200 µm) and dense specimens. Polished sections of the SiOC samples were prepared to study, by energy-dispersive X-ray spectroscopy (EDXS) and nanoindentation, how the elemental composition, hardness, and elastic modulus vary from the surface toward the bulk. For both compositions, pyrolysis in CO2 leads to a strong decrease in the hardness and elastic modulus. The hardness of both the samples pyrolyzed in CO2 approaches the typical value for fused silica, suggesting that CO2 selectively breaks the Si–C and Si–N bonds and leads to the formation of a silica-like network. EDXS and nanoindentation reveal that the modification induced by the CO2 flow extends below the surface at least for a thickness of about 30 µm.

Effect of the pyrolysis atmosphere on the mechanical properties of polymer-derived SiOC and SiCN / Soraru, G. D.; Tavonatti, C.; Kundanati, L.; Pugno, N.; Biesuz, M.. - In: JOURNAL OF THE AMERICAN CERAMIC SOCIETY. - ISSN 0002-7820. - 2020 103:(2020), pp. 6519-6530. [10.1111/jace.17392]

Effect of the pyrolysis atmosphere on the mechanical properties of polymer-derived SiOC and SiCN

Soraru G. D.;Kundanati L.;Pugno N.;Biesuz M.
2020-01-01

Abstract

Mechanical properties of polymer-derived ceramics are usually measured on samples pyrolyzed in inert atmosphere. Here, we report the hardness and elastic modulus of SiOC and SiCN pyrolyzed in both inert (Ar) and reactive (CO2) atmosphere. The external surface of the specimens exposed to the pyrolysis gas was characterized by Vickers microhardness measurements and infrared spectroscopy. The elastic modulus was evaluated by three-point bending tests on thin (150-200 µm) and dense specimens. Polished sections of the SiOC samples were prepared to study, by energy-dispersive X-ray spectroscopy (EDXS) and nanoindentation, how the elemental composition, hardness, and elastic modulus vary from the surface toward the bulk. For both compositions, pyrolysis in CO2 leads to a strong decrease in the hardness and elastic modulus. The hardness of both the samples pyrolyzed in CO2 approaches the typical value for fused silica, suggesting that CO2 selectively breaks the Si–C and Si–N bonds and leads to the formation of a silica-like network. EDXS and nanoindentation reveal that the modification induced by the CO2 flow extends below the surface at least for a thickness of about 30 µm.
2020
Soraru, G. D.; Tavonatti, C.; Kundanati, L.; Pugno, N.; Biesuz, M.
Effect of the pyrolysis atmosphere on the mechanical properties of polymer-derived SiOC and SiCN / Soraru, G. D.; Tavonatti, C.; Kundanati, L.; Pugno, N.; Biesuz, M.. - In: JOURNAL OF THE AMERICAN CERAMIC SOCIETY. - ISSN 0002-7820. - 2020 103:(2020), pp. 6519-6530. [10.1111/jace.17392]
File in questo prodotto:
File Dimensione Formato  
jace.17392.pdf

Solo gestori archivio

Descrizione: Articolo
Tipologia: Versione editoriale (Publisher’s layout)
Licenza: Tutti i diritti riservati (All rights reserved)
Dimensione 1.18 MB
Formato Adobe PDF
1.18 MB Adobe PDF   Visualizza/Apri

I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione

Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11572/275128
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 19
  • ???jsp.display-item.citation.isi??? 17
social impact