Investigation of strong shock wave interactions with CeO2 ceramic

Abstract

Strong shock wave interactions with ceramic material ceria (CeO 2 ) in presence of O 2 and N 2 gases were investigated using free piston driven shock tube (FPST). FPST is used to heat the test gas to very high temperature of about 6800-7700 K (estimated) at pressure of about 6.8-7.2 MPa for short duration (2-4 ms) behind the reflected shock wave. Ceria is subjected to super heating and cooling at the rate of about 10 6 K/s. Characterization of CeO 2 sample was done before and after exposure to shock heated test gases (O 2 and N 2 ). The surface composition, crystal structure, electronic structure and surface morphology of CeO 2 ceramic were examined using X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectrometry, scanning electron microscopy (SEM) and high resolution transmission electron microscopy (HRTEM). Results obtained from the experimental investigations show that CeO 2 can withstand high pressure accompanied by thermal shock without changing its crystal structure. Reducible CeO 2 releases lattice oxygen making it possible to shift between reduced and oxidized states upon the interaction with shock heated gas. Due to such reaction mechanism, CeO 2 ceramic undergoes nitrogen doping with decrease in lattice parameter. Investigations reveal that CeO 2 retains its crystal structure during strong shock interaction, even at elevated pressure.

Shock wave‐material interaction in ZrB2–SiC based ultra high temperature ceramics for hypersonic applications

“…[16][17][18][19][20][21][22] For example, Jayaram et al performed FPST experiments on hot pressed ZrB 2 -SiC-MoSi 2 ceramic for hypersonic re-entry applications in argon-oxygen environment and reported surface oxidation. [16][17][18][19][20][21][22] For example, Jayaram et al performed FPST experiments on hot pressed ZrB 2 -SiC-MoSi 2 ceramic for hypersonic re-entry applications in argon-oxygen environment and reported surface oxidation.…”

“…18 Analogously, shock compression testing by Vasu et al on metal chalcogenides (MoS 2 , WS 2 and MoSe 2 ) exhibited changes in structure and vibrational spectra, along with reduction in interplanar spacing. 22 Thus, the interaction of gaseous shock wave with materials can result in crystallographic modifications, formation of new crystalline/amorphous phases, and/or oxidation. 22 Thus, the interaction of gaseous shock wave with materials can result in crystallographic modifications, formation of new crystalline/amorphous phases, and/or oxidation.…”

“…Shock tubes are employed in the area of material science for synthesis and testing of materials at elevated loading conditions. [16][17][18][19][20][21][22] For example, Jayaram et al performed FPST experiments on hot pressed ZrB 2 -SiC-MoSi 2 ceramic for hypersonic re-entry applications in argon-oxygen environment and reported surface oxidation. 16 Also, Vishakantaiah and Reddy studied the catalytic effect of CeO 2 stabilized ZrO 2 using FPST, and showed the occurrence of phase transformation.…”

“…19 In another set of investigation, exposure of shock heated oxygen to combustion synthesized zirconia and titania revealed phase transformation from cubic to monoclinic 20 and anatase to rutile, 21 respectively, while cubic ceria under similar conditions did not undergo phase transformation. 22 Thus, the interaction of gaseous shock wave with materials can result in crystallographic modifications, formation of new crystalline/amorphous phases, and/or oxidation. In case, a material shows detrimental failure in shock tube testing, its potential for hypersonic application is ruled out in the preliminary stages of material screening.…”

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

“…This pyrochlore (Ce 2 Zr 2 O 7 ) compound can be derived from Ce 2 Zr 2 O 8 with a loss of one oxygen atom. 16 Cubic CeO 2 has been proved to be a strong shock absorbing material without changing its crystal structure, 17 whereas cubic ZrO 2 transforms to monoclinic ZrO 2 phase due to interaction with shock-heated test gases. 18 Shock-treated Zr remains in +4 oxidation state.…”