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Amorphous, Monoclinic, and Tetragonal Porous Zirconia Through a Controlled Self‐Sustained Combustion Route
Author(s) -
Raghavendra Venugopal B.,
Naik Swati,
Antony Meera,
Ramalingam Gopalakrishnan,
Rajamathi Michael,
Raghavan Srinivasan
Publication year - 2011
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1551-2916.2010.04334.x
Subject(s) - monoclinic crystal system , tetragonal crystal system , cubic zirconia , materials science , porosity , amorphous solid , combustion , chemical engineering , mineralogy , composite material , crystallography , crystal structure , chemistry , ceramic , engineering
Porous, large surface area, metastable zirconias, are of importance to catalytic, electrochemical, biological, and thermal insulation applications. Combustion synthesis is a very commonly used method for producing such zirconias. However, its rapid nature makes control difficult. A simple modification has been made to traditional solution combustion synthesis to address this problem. It involves the addition of starch to yield a starting mixture with a “dough‐like” consistency. Just 5 wt% starch is seen to significantly alter the combustion characteristics of the “dough.” In particular, it helps to achieve better control over reaction zone temperature that is significantly lower than the one calculated by the adiabatic approximation typically used in self‐propagating high‐temperature synthesis. The effect of such control is demonstrated by the ability to tune dough composition to yield zirconias with different phase compositions from the relatively elusive “amorphous” to monoclinic (>30 nm grain size) and tetragonal pure zirconia (<30 nm grain size). The nature of this amorphous phase has been investigated using infrared spectroscopy. Starch content also helps tailor porosity in the final product. Zirconias with an average pore size of about 50 μm and specific surface area as large as 110 m 2 /g have been obtained.