Precipitation synthesis and sintering of yttria nanopowders

Huang, Zhenguo; Sun, Xudong; Xiu, Zhimeng; Chen, Shaowei; Tsai, Chi-Tay

doi:10.1016/j.matlet.2004.02.008

Cited by 110 publications

(64 citation statements)

References 24 publications

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“…TGA shows a mass loss of about 33% between room temperature and 700°C, while DSC shows an exothermic phase transition at about 665°C, which is believed to be due to the formation of crystalline Y 2 O 3 . The initial yttrium carbonate is believed to decompose according to: [7,8] …”

Section: Resultsmentioning

confidence: 99%

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Irreversible phase transitions in doped metal oxides for use as temperature sensors in explosions

Eilers

Gunawidjaja

Myint

et al. 2012

AIP Conference Proceedings

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Abstract. The temperature of post-detonation fireballs produced by advanced energetic formulations is commonly determined using optical methods such as pyrometry and spectral line fitting. These methods are noninvasive and provide an average temperature predominantly from the surface of the fireball. However, for many applications the ability to probe the internal temperature as well as temperature gradients within the fireball is highly desirable. One such method that has shown promise in providing this information is seeding micron to nano-sized temperature sensors into the fireball which can be collected post-detonation and analyzed to determine a temperature profile. In this work, disordered rare-earth-doped metal oxide nanoparticles were synthesized and subjected to various types of heat treatment, including furnace heating, T-Jump (fast pyroprobe), and explosive heating. The heat treatment leads to irreversible phase transitions which are monitored by optically active rare-earth dopants. Eu 3+ in particularly is a well-known probe ion. Optical signatures are evaluated to monitor phase transitions (disorder-order) in the nanoparticles. For Y 2 O 3 :Eu, the peak position and peak width of the excitation spectra appear to be the most promising indicators for the temperature.

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Section: Resultsmentioning

confidence: 99%

“…Eu dopants are often used to monitor structural changes in materials. [3][4][5][6] [7] The pH is adjusted to reach a final value of 7.5 -8.0. After aging for three hours at room temperature and under continuous stirring, white precipitates are washed with DIwater (3x) and acetone (1x).…”

Section: Introductionmentioning

confidence: 99%

Irreversible phase transitions in doped metal oxides for use as temperature sensors in explosions

Eilers

Gunawidjaja

Myint

et al. 2012

AIP Conference Proceedings

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“…However the % closed porosity was found to be excessively high in the citric acid and urea fuels. The differential rate of lattice diffusion of Y 3+ and Yb 3+ ions and grain growth kinetics 16) vary with respect to the combustion efficiency of the fuel causing variations in the % closed pores with respect to the fuels. Infact, the removal of the entrapped pores usually required high sintering temperatures.…”

Section: +mentioning

confidence: 99%

Sintering, microstructural and mechanical characterization of combustion synthesized Y2O3 and Yb3+-Y2O3

Mangalaraja

Ananthakumar

Mouzon

et al. 2009

J. Ceram. Soc. Japan

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The present work highlights the microstructural features and mechanical properties of Y2O3 prepared with and without Yb 3+ doping that processed through combustion synthesis involving various organic fuels such as urea, citric acid and glycine. Properties such as powder-flow, particle packing, green density, % of shrinkage, sintered density, grain size, Vicker's microhardness (Hv) and fracture toughness (KIC) were analyzed and compared with respect to the fuel sources. The as combusted precursors were calcined at 1100°C for 4 h under oxygen atmosphere to obtain fully crystalline Y2O3 powders. Cylindrical pellets were fabricated as test specimens and sintered at 1600°C for 3 h. The SEM images of the sintered yttria samples show an average grain size of < 3 μm irrespective of the fuels. However, the mechanical properties show significant dependence on the fuels used. A maximum hardness of 6.8 ± 0.1 and 7.0 ± 0.1 GPa was obtained for Y2O3 and Yb 3+ doped Y2O3 derived from glycine fuel. Whereas the maximum fracture toughness of 2.6 ± 0.3 MPa m 1/2 was obtained for the samples derived from urea. The Yb 3+ doping found to increase the bulk hardness of yttria from 0.2 to 0.6 GPa. The study contributes to appropriately select the fuels for obtaining high dense, mechanically stable yttria ceramics through combustion process.

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“…In view of this point, yttria is still attractive in investigations of newer and better processing routes for its synthesis in the nano-crystalline range. For the practical application of yttria-based ceramics, the synthesis of yttria powders with controlled characteristics is necessary in order to obtain a dense sintered product at a lower sintering temperature [11,12].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of nanocrystalline yttria powder prepared by a polymer solution route

2011

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Nanometer-scaled yttria (Y2O3) powders were synthesized by a polymer solution route using polyvinyl alcohol (PVA) as an organic carrier. The PVA polymer contributed to a soft and porous powder microstructure, and homogeneous precursor gels containing PVA polymer were effective in making nanometer-sized yttria powders. In this process, the content of PVA and the calcination temperature strongly affected the microstructure and crystallization behavior of the yttria powders. The homogeneous precursors were crystallized to a stable yttria phase at 600°C for 1 h. In this paper, a simple solution technique for the fabrication of nanometer-sized yttria powders is introduced. The effects of PVA on the powder morphology and on powder specific surface area were studied. The characterization of the synthesized powders was examined by using XRD, DTA/TG, SEM, TEM, a particle size analyzer and nitrogen gas adsorption. The yttria powder synthesized from PVA with a content ratio of 4:1 revealed a crystallite size of about 15 nm with a high surface area of 34.71 m 2 /g.

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Precipitation synthesis and sintering of yttria nanopowders

Cited by 110 publications

References 24 publications

Irreversible phase transitions in doped metal oxides for use as temperature sensors in explosions

Irreversible phase transitions in doped metal oxides for use as temperature sensors in explosions

Sintering, microstructural and mechanical characterization of combustion synthesized Y2O3 and Yb3+-Y2O3

Synthesis of nanocrystalline yttria powder prepared by a polymer solution route

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