TY - JOUR
T1 - Structural and thermodynamic analysis of metal filler incorporations in SiaOb(M)cCd polymer derived ceramics
T2 - Ta, Hf, Nb
AU - Leonel, Gerson J.
AU - Scharrer, Manuel
AU - Singh, Gurpreet
AU - Navrotsky, Alexandra
N1 - Publisher Copyright:
© 2023 The American Ceramic Society.
PY - 2023/11/1
Y1 - 2023/11/1
N2 - This work systematically investigates the thermodynamic stability of SiaOb(M)cCd structures 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)cCd specimens 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.
AB - This work systematically investigates the thermodynamic stability of SiaOb(M)cCd structures 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)cCd specimens 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.
KW - phase equilibria
KW - silicon oxycarbide
KW - thermodynamics
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U2 - 10.1111/ijac.14476
DO - 10.1111/ijac.14476
M3 - Article
AN - SCOPUS:85162925417
SN - 1546-542X
VL - 20
SP - 3395
EP - 3406
JO - International Journal of Applied Ceramic Technology
JF - International Journal of Applied Ceramic Technology
IS - 6
ER -