Synthesis of monodisperse CeO2–ZrO2 particles exhibiting cyclic superelasticity over hundreds of cycles |
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| Authors: | Zehui Du Pengcheng Ye Xiao Mei Zeng Christopher A. Schuh Nobumichi Tamura Xinran Zhou Chee Lip Gan |
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| Affiliation: | 1. Temasek Laboratories, Nanyang Technological University, Singapore, Singapore;2. School of Materials Science and Engineering, Nanyang Technological University, Singapore, Singapore;3. Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts;4. Advanced Light Source (ALS), Lawrence Berkeley National Laboratory (LBNL), Berkeley, California |
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| Abstract: | Nano‐ and microscale CeO2–ZrO2 (CZ) shape memory ceramics are promising materials for smart micro‐electro‐mechanical systems (MEMS), sensing, actuation and energy damping applications, but the processing science for scalable production of such small volume ceramics has not yet been established. Herein, we report a modified sol‐gel method to synthesize highly monodisperse spherical CZ particles with diameters in the range of ~0.8‐3.0 μm. Synchrotron X‐ray micro‐diffraction (μSXRD) confirmed that most of the particles are single crystal after annealing at 1450°C. Having a monocrystalline structure and a small specimen length scale, the particles exhibit significantly enhanced shape memory and superelasticity properties with up to ~4.7% compression being completely recoverable. Highly reproducible superelasticity through over five hundred strain cycles, with dissipated energy up to ~40 MJ/m3 per cycle, is achieved in the CZ particles containing 16 mol% ceria. This cycling capability is enhanced by ten times compared with our first demonstration using micropillars (only 50 cycles in Lai et al, Science, 2013, 341, 1505). Furthermore, the effects of cycling and testing temperature (in 25°C‐400°C) on superelasticity have been investigated. |
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| Keywords: | CeO2– ZrO2 particles shape memory sol‐gel superelasticity |
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