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Catalytic Effect of CeO2-Stabilized ZrO2 Ceramics with Strong Shock-Heated Mono- and Di-Atomic Gases

Vishakantaiah, Jayaram and Reddy, Kalidevapura Polareddy Jagannatha (2016) Catalytic Effect of CeO2-Stabilized ZrO2 Ceramics with Strong Shock-Heated Mono- and Di-Atomic Gases. In: JOURNAL OF THE AMERICAN CERAMIC SOCIETY, 99 (12). pp. 4128-4136.

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Official URL: http://dx.doi.org/10.1111/jace.14454

Abstract

The reducibility of synthesized ceria-stabilized zirconia (CSZ) with strong shock-heated test gases is investigated. Free piston-driven shock tube operating at hypersonic speed at Mach number of 6-8 has been used to heat the ultrahigh pure test gases like Ar to similar to 12800 K, N-2 to similar to 7960 K, and O-2 to similar to 5500 K at a medium reflected shock pressure (5.0-7.4 MPa) for a short duration of 1-2 ms test time. Under this extreme thermodynamic condition, test gases undergo real gas effects. The structural and spectroscopic investigations of CSZ (Ce2Zr2O8) after interaction with shock-heated argon gas show pyrochlore structure of Ce2Zr2O7-delta which is observed to be black in color. In presence of shock-heated N-2 gas, CSZ remains in fluorite structure by changing its color to pale green as nitrogen atoms fill oxygen vacancies. After O-2 interaction with the shock wave, CSZ remains pale yellow but the X-ray diffraction pattern shows the presence of monoclinic ZrO2 due to phase separation. During reduction process, Ce4+ has been reduced to Ce3+ which is an unusual effect. In this study, the catalytic and surface recombination effects of CSZ due to shock-induced compression in millisecond timescale are presented.

Item Type: Journal Article
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Additional Information: Copy right for this article belongs to the WILEY-BLACKWELL, 111 RIVER ST, HOBOKEN 07030-5774, NJ USA
Department/Centre: Division of Chemical Sciences > Solid State & Structural Chemistry Unit
Division of Mechanical Sciences > Aerospace Engineering (Formerly, Aeronautical Engineering)
Date Deposited: 15 Mar 2017 04:51
Last Modified: 15 Mar 2017 04:51
URI: http://eprints.iisc.ernet.in/id/eprint/56395

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