The presence of FeCl2 catalyst enabled the growth of onedimensional nanostructures directly during the pyrolysis of highly porous monoliths, produced from a polysiloxane preceramic polymer with the aid of a gas-generating porogen. Either silicon nitride or silicon carbide nanowires were formed, with a length of several micrometers, depending on the processing atmosphere. Increasing the pyrolysis temperature caused an increase in the length and the amount of nanostructures produced. The remaining matrix consisted of an incompletely crystallized Si–O–C phase, containing SiC crystals and either graphitic (N2 pyrolysis) or amorphous carbon (Ar pyrolysis). X-ray diffraction data and high-resolution transmission electron microscopy investigations combined with electron energy loss and energydispersive X-ray spectroscopy methods enabled to ascertain the growth mechanisms for the nanowires, which depended on the pyrolysis atmosphere (gas phase reaction for N2 pyrolysis; vapor–liquid–solid for Ar pyrolysis).

Growth of One-Dimensional Nanostructures in Porous Polymer-Derived Ceramics by Catalyst-Assisted Pyrolysis. Part I: Iron Catalyst

COLOMBO, PAOLO
2010

Abstract

The presence of FeCl2 catalyst enabled the growth of onedimensional nanostructures directly during the pyrolysis of highly porous monoliths, produced from a polysiloxane preceramic polymer with the aid of a gas-generating porogen. Either silicon nitride or silicon carbide nanowires were formed, with a length of several micrometers, depending on the processing atmosphere. Increasing the pyrolysis temperature caused an increase in the length and the amount of nanostructures produced. The remaining matrix consisted of an incompletely crystallized Si–O–C phase, containing SiC crystals and either graphitic (N2 pyrolysis) or amorphous carbon (Ar pyrolysis). X-ray diffraction data and high-resolution transmission electron microscopy investigations combined with electron energy loss and energydispersive X-ray spectroscopy methods enabled to ascertain the growth mechanisms for the nanowires, which depended on the pyrolysis atmosphere (gas phase reaction for N2 pyrolysis; vapor–liquid–solid for Ar pyrolysis).
File in questo prodotto:
Non ci sono file associati a questo prodotto.
Pubblicazioni consigliate

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/11577/2423340
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 107
  • ???jsp.display-item.citation.isi??? 104
social impact