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  • Structural and thermodynamic analysis of metal filler incorporations in Si a O b (M) c C d polymer derived ceramics: Ta, Hf, Nb
Title: Structural and thermodynamic analysis of metal filler incorporations in Si a O b (M) c C d polymer derived ceramics: Ta, Hf, Nb
Abstract This work systematically investigates the thermodynamic stability of SiaOb(M)cCdstructures derived from polymeric precursors incorporating metal fillers: Ta, Nb, and Hf, at 1200 and 1500°C. Structural characterization of the polymer derived ceramics (PDCs) employs X‐ray diffraction, Fourier transform infrared spectroscopy, and X‐ray photoelectron spectroscopy. Enthalpies of formation relative to crystalline components (metal oxide, silica, silicon carbide, and graphite) are obtained from thermodynamic measurements by high temperature oxide melt solution calorimetry. The enthalpies of formation (∆H°f, comp) of Ta‐1200, Hf‐1200, Nb‐1200, Ta‐1500, Hf‐1500, and Nb‐1500 specimens are −137.82 ± 9.72, −256.31 ± 8.97, −82.80 ± 9.82, −182.80 ± 7.85, −292.54 ± 9.38, −224.98 ± 9.60 kJ/mol, respectively. Overall incorporation of Hf results in most thermodynamically stable structures at all synthesis temperatures. SiaOb(M)cCdspecimens employing Nb fillers undergo the most stable structural evolution in this temperature range. The results indicate strong thermodynamic drive for carbothermal reduction of metal oxide domains. Incorporation of Ta provides the greatest stabilization of SiO3C mixed bonding environments. Ultimately, the choice of metal filler influences composition, structural evolution, and thermodynamic stability in PDCs.  more » « less
Award ID(s):
1743701
PAR ID:
10469318
Author(s) / Creator(s):
; ; ;
Publisher / Repository:
Wiley
Date Published:
Journal Name:
International Journal of Applied Ceramic Technology
Volume:
20
Issue:
6
ISSN:
1546-542X
Page Range / eLocation ID:
3395 to 3406
Format(s):
Medium: X
Sponsoring Org:
National Science Foundation
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