Thermodynamic Analysis of the CaO–Y2O3–ZrO2–Ti–Fe2O3 System as a Precursor for SHS-Produced Pyrochlore-Based Ceramics.

Autor: Podbolotov, K. B., Barinova, T. V., Khina, B. B., Velichko, M. V.
Zdroj: International Journal of Self-Propagating High-Temperature Synthesis; Oct2019, Vol. 28 Issue 4, p239-244, 6p
Abstrakt: The paper reports on the thermodynamic analysis of the CaO–Y2O3–ZrO2–Ti–Fe2O3 system as a precursor for SHS-produced pyrochlore-based ceramics. Adiabatic combustion temperature Tad and equilibrium concentration of pyrochlore were first calculated for the quasi-ternary system Y2O3–ZrO2–(Ti + Fe2O3) containing no CaO. It was found that, in the presence of CaO, a best yield of Zr-enriched pyrochlore ceramic can be reached within the following domain of green compositions (wt %): CaO 2.5–5.0, Y2O3 22.5–35.0, ZrO2 7.5–22.5, and (40% Ti + 60% Fe2O3) 45.0–60.0; within this domain, Tad = 2100–2400°K. Although in control experiments Tad was found to be within the range 1700–1970 K, nevertheless the combustion products always showed the presence of pyrochlore-based ceramic, as predicted by thermodynamic analysis. [ABSTRACT FROM AUTHOR]
Databáze: Complementary Index
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