Experimental study of the effect of strong shock heated test gases with cubic zirconia
V. Jayaram1*, K. P. J. Reddy2
1Shock Induced Materials Chemistry Lab, Solid State and Structural Chemistry Unit, Indian Institute of Science, Bangalore 560012, India
2Laboratory for Hypersonic and Shock Wave Research, Department of Aerospace Engineering, Indian Institute of Science, Bangalore 560012, India
Adv. Mater. Lett., 2017, 8 (2), pp 150-155
Publication Date (Web): Dec 27, 2016
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This paper presents a novel method of interaction of zirconia with strong shock wave in presence of dissociated/non-dissociated gas species for short duration using shock tube. Cubic zirconia (c-ZrO2) was synthesized by solution combustion method and exposed to strong shock heated N2 and O2 test gases in a free piston driven shock tube (FPST). FPST is used to heat the test gases to very high temperature of about 7540-9530 K (estimated) and reflected shock pressure of about 65-70 bar for short duration (2-3 ms). X-ray diffraction (XRD) study shows the phase transformation of c-ZrO2 to m-ZrO2. Scanning electron microscopy (SEM) images shows the formation of sharp nano/micro zirconia needles due to melting and nucleation during super heating and cooling at the rate of about 106 K/s. These types of sharp nano/micro needles are observed for the first time in this shock tube experiment. X-ray photoelectron spectroscopy (XPS) and Fourier transform infrared (FTIR) spectroscopy show no change in electronic structure and chemical composition of ZrO2 which indicates that the reaction is fully catalytic. This unique experimental methodology can be used to study the chemistry of materials under extreme thermodynamic conditions which is of seminal importance in space, nuclear and other high temperature applications.
Phase transformation, shock heated gas, gas-solid interaction, nano/micro zirconia needles, aerothermodynamic reactions.