AI Chat Paper
Discover the SciOpen Platform and Achieve Your Research Goals with Ease.
Search articles, authors, keywords, DOl and etc.
{{expandStatus?'Exit ':''}}Advanced Search
• Dual-phase microstructure is responsible for transparency.
• Miscibility gap results mutual solubility in nucleation by liquid-phase sintering.
• Residual oxygen vacancies in fully densified microstructure can also absorpt the visible light.
The A2B2O7 series of ternary oxides are derivatives of fluorite structure over a wide range of rA/rB. Competing by two rare-earths the A-site, La2-xLuxZr2O7 ceramics were found transparent only in pore-free microstructures with similar grain sizes of pyrochlore (PY) and defective fluorite (DF) phases. Mutual solubilities of Lu and La in both phases were found by imaging and energy-dispersive spectroscopy analysis in scanning electron microscope. The dual-phase microstructures were developed with liquid-phase resulted from the exothermal reactions, creating a miscibility gap between two structures to moderate their competing grain growth. Change in grain growth behaviors in liquid-phase is described by a nucleation line in La2Zr2O7‒Lu2Zr2O7 phase diagram. Variations of solution levels in DF grains and co-existing of dual-phase grain clusters in common orientation were revealed in transparent ceramics by electron backscattered diffraction, resulted by epitaxial relation of two phases promoted by the liquid-phase. Oxygen vacancies and various hole states common in both phases were revealed by characteristic cathodoluminescence peaks. The collective effects of pores, phase and grain boundaries, oxygen vacancies on scattering or absorption of visible light enables to establish a hierarchical microstructure‒transparency relationship in such complex oxide ceramics, which could be tailored or further optimized by controllable sintering.
Zhu DM, Miller RA. Development of advanced low conductivity thermal barrier coatings. Int J Appl Ceram Technol 2004;1:86-94.
Clarke DR, Phillpot SR. Thermal barrier coating materials. Mater Today 2005;8:22-9.
Feng T, Clarke DR, Jiang D. Neodymium zirconate (Nd2Zr2O7) transparent ceramics as a solid state laser material. Appl Phys Lett 2011;98:151105.
Chaudhry A, Canning A, Boutchko R. First-principles studies of Ce-doped RE2M2O7 (RE = Y, La; M = Ti, Zr, Hf): a class of non-scintillators. J Appl Phys 2011;109. 083708.
Shimamura K, Arima T, Idemitsu K. Thermophysical properties of rare-earth-stabilized zirconia and zirconate pyrochlores as surrogates for actinide-doped zirconia. Int J Thermophys 2007;28:1074-84.
Blanchard PER, Clements R, Kennedy BJ. Does local disorder occur in the pyrochlore zirconates. Inorg Chem 2012;51:13237-44.
Zhang AY, Lu MK. Systematic research on RE2Zr2O7 (RE=La, Nd, Eu and Y) nanocrystals: preparation, structure and photoluminescence characterization. Solid State Sci 2008;10:74-81.
Wang ZJ, Zhou GH. Fabrication and phase transition of La2-xLuxZr2O7 transparent ceramics. J Eur Ceram Soc 2014;34:3951-8.
Subramanian MA, Aravamudan G, Subba Rao GV. Oxide pyrochlores - a review. Prog Solid State Chem 1983;15:55-143.
Pvan Dijk M, Jde Vries K, JBurggraaf A. Oxygen ion and mixed conductivity in compounds with the fluorite and pyrochlore structure. Solid State Ionics 1983;9–10:913-20.
Chen H, Liu Y, Gao Y, Tao S, Luo H. Design, preparation, and characterization of graded YSZ/La2Zr2O7 thermal barrier coatings. J Am Ceram Soc 2010;93:1732-40.
Lehmann Henry, Pitzer Dieter. Thermal conductivity and thermal expansion coefficients of the lanthanum rare-earth-element zirconate system. J Am Ceram Soc 2003;86:1338-44.
Liu L, Fan L. The immobilization of triuranium octoxide by gadolinium zirconate. Nucl Technol 2016;193:430-3.
Govindan Kutty KV, Asuvathraman R. Actinide immobilization in crystalline matrix: a study of uranium incorporation in gadolinium zirconate. J Phys Chem Solid 2005;66:596-601.
Vasil’eva MF, Gerasyuk AK. Using new film-forming materials-Gadolinium zirconate and lutetium zirconate- to obtain high-quality optical coatings. J Opt Technol 2007;74:712-6.
Radha AV, Ushakov Sergey V. Thermochemistry of lanthanum zirconate pyrochlore. J Mater Res 2009;24:3350-7.
Saradhi MP, Ushakov SV. Fluorite-pyrochlore transformation in Eu2Zr2O7-direct calorimetric measurement of phase transition, formation and surface enthalpies. RSC Adv 2012;2:3328-34.
Zhao WW, Zhang KB. Fabrication and optical properties of transparent LaErZr2O7 ceramic with high excess contents of La and Er. Ceram Int 2019;45:11717-22.
Wang SM, Zhou GJ. Synthesis and characterization of lanthanum stannate nanoparticles. J Am Ceram Soc 2006;89:2956-9.
Petrik NG, Taylor DP, Orlando TM. Laser-stimulated luminescence of yttria-stabilized cubic zirconia crystals. J Appl Phys 1999;85:6770-6.
Boffelli M, Zhu W, Sponchia M Back G, Francese T, Riello P, Benedetti A, Pezzotti G. Oxygen hole states in zirconia lattices: quantitative aspects of their cathodoluminescence emission. J Phys Chem 2014;118:9828-36.
Gu H. Chemical structure of grain-boundary layer in SrTiO3 and its segregation-induced transition: a continuum interface approach. Chin Phys B 2018;27:5-14.
Tian T, Cheng LH, Zheng LY, Xing JJ, Gu H, Bernik S. Defect engineering for a markedly increased electrical conductivity and power factor in doped ZnO ceramic. Acta Mater 2016;82:136-44.
This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).
京公网安备11010802044758号