The HF etching of a silicon(boron)oxycarbide glass was, for the first time, followed in situ by synchrotron radiation X-ray diffraction. The starting Si(B)OC glass is formed by two interpenetrating nano-sized networks, one SiO2-rich and the other C-rich comprising β-SiC nanocrystals and nanocrystalline graphite. The silica-based phase is dissolved by the HF forming a porous C-rich Si(B)OC. The XRD analysis shows the quantitative evolution with the etching time of all nanocrystalline phases, including the amorphous SiO2-based one. The rate-limiting step for the dissolution is the diffusion of the reactants/products through the porous C-rich Si(B)OC. The XRD analysis shows also a trend of the basal spacing of the sp2 carbon phase as a function of the dissolution time suggesting the presence, in the un-etched glass, of a in-plane residual compressive stress which is relaxed by etching out the SiO2–based network. At the end of the dissolution process the BET analysis shows the formation of a micro-meso porous C-rich Si(B)OC with a SSA of 595 m2/g, mesopore size in the range 2-10 nm and pore volume of 0.863 cm3/g.

C-rich micro/mesoporous Si(B)OC: in situ diffraction analysis of the HF etching process / Sorarù, Gian Domenico; R., Pena Alonso; Leoni, Matteo. - In: MICROPOROUS AND MESOPOROUS MATERIALS. - ISSN 1387-1811. - STAMPA. - 172:(2013), pp. 125-130. [10.1016/j.micromeso.2013.01.026]

C-rich micro/mesoporous Si(B)OC: in situ diffraction analysis of the HF etching process

Sorarù, Gian Domenico;Leoni, Matteo
2013-01-01

Abstract

The HF etching of a silicon(boron)oxycarbide glass was, for the first time, followed in situ by synchrotron radiation X-ray diffraction. The starting Si(B)OC glass is formed by two interpenetrating nano-sized networks, one SiO2-rich and the other C-rich comprising β-SiC nanocrystals and nanocrystalline graphite. The silica-based phase is dissolved by the HF forming a porous C-rich Si(B)OC. The XRD analysis shows the quantitative evolution with the etching time of all nanocrystalline phases, including the amorphous SiO2-based one. The rate-limiting step for the dissolution is the diffusion of the reactants/products through the porous C-rich Si(B)OC. The XRD analysis shows also a trend of the basal spacing of the sp2 carbon phase as a function of the dissolution time suggesting the presence, in the un-etched glass, of a in-plane residual compressive stress which is relaxed by etching out the SiO2–based network. At the end of the dissolution process the BET analysis shows the formation of a micro-meso porous C-rich Si(B)OC with a SSA of 595 m2/g, mesopore size in the range 2-10 nm and pore volume of 0.863 cm3/g.
2013
Sorarù, Gian Domenico; R., Pena Alonso; Leoni, Matteo
C-rich micro/mesoporous Si(B)OC: in situ diffraction analysis of the HF etching process / Sorarù, Gian Domenico; R., Pena Alonso; Leoni, Matteo. - In: MICROPOROUS AND MESOPOROUS MATERIALS. - ISSN 1387-1811. - STAMPA. - 172:(2013), pp. 125-130. [10.1016/j.micromeso.2013.01.026]
File in questo prodotto:
File Dimensione Formato  
163-IN SITU XRD HF.pdf

Solo gestori archivio

Descrizione: Articolo completo
Tipologia: Versione editoriale (Publisher’s layout)
Licenza: Tutti i diritti riservati (All rights reserved)
Dimensione 548.9 kB
Formato Adobe PDF
548.9 kB 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/11572/96365
Citazioni
  • ???jsp.display-item.citation.pmc??? ND
  • Scopus 32
  • ???jsp.display-item.citation.isi??? 30
social impact