X-ray induced color change on dense yttria samples obtained by spark plasma sintering

Attia, Mohamed A.; Garroni, Sebastiano; Chiriu, Daniele; Ricci, Pier Carlo; Delogu, Francesco; Orrù, Roberto; Cao, Giacomo

doi:10.1016/j.cplett.2014.11.009

Cited by 7 publications

(5 citation statements)

References 49 publications

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“…For example, alumina tends to have dark grey surface (entirely or in ring shape), or yttria stabilised zirconia emits red colour when exposed to X-rays (unpublished data). This phenomenon is found to have a significant influence on transparent ceramics [197], and hence studied extensively. In all cases with transparent ceramics, the surfacing effect can be attributed to oxygen deficiency owing to the reducing ambient of PECS process.…”

Section: Synthesis Of W20o58 and Its Composites With Zro2mentioning

confidence: 97%

“…dark regions emerge in the sintered oxides. If it is controlled, it allows synthesis of substoichiometric compounds, e.g., oxygen deficient metal oxides with unique emitting properties [197]. In addition to formation of CO, possible reactions between the mould and the sintered powder is prevented by inserting graphite foil or hBN powder in between.…”

Section: Pulsed Electric Current Sinteringmentioning

confidence: 99%

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Al2O3–cBN composites sintered by SPS and HPHT methods

Klimczyk

Cura

Vlaicu

et al. 2016

Journal of the European Ceramic Society

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Section: Synthesis Of W20o58 and Its Composites With Zro2mentioning

confidence: 97%

Section: Pulsed Electric Current Sinteringmentioning

confidence: 99%

Al2O3–cBN composites sintered by SPS and HPHT methods

Klimczyk

Cura

Vlaicu

et al. 2016

Journal of the European Ceramic Society

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“…Solid-state methods include the sintering of metal powder. It is well known that spark plasma sintering (SPS) decreases the sintering time and temperature, compared with sintering in an electric furnace, resulting in suppression of grain growth during sintering [ 22 , 23 , 24 , 25 ]. Therefore, it is worthwhile to investigate the microstructure and mechanical properties of aluminum foam processed by SPS.…”

Section: Introductionmentioning

confidence: 99%

Structural, Electrical, and Mechanical Properties Investigation of Open-Cell Aluminum Foams Obtained by Spark Plasma Sintering and Replication on Polyurethane Template

et al. 2022

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The present paper illustrates a comparison of open-cell aluminum foams. The foams were fabricated by two different methods: spark plasma sintering and replication on a polyurethane template. The influence of pressure, temperature, and diameter of space holding material on foam obtained by the spark plasma sintering method was investigated. Additionally, the aluminum powder content in slurry and atmosphere during thermal processing of foam prepared by the replication technique were studied. The morphology and structure of obtained samples were analyzed by scanning electron microscopy and X-ray diffraction analysis. Supplementarily, mechanical properties and electrical conductivity were studied. The porosity of obtained samples was 83% for the SPS sample and 85% for the replication sample. The results of the studies carried out gave us an understanding that the SPS method is more promising for using the obtained foams as cathode current collectors in lithium-ion batteries due to excessive aluminum oxidation during sintering in the furnace.

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“…In general, a reduction of QY is observed with decreasing size of nanoparticles depending on synthesis method and lowering of crystallinity. [8][9][10] Tb 3þ ions has been considered as good candidate to cover the green region instead of Er 3þ and a codoping with Yb 3þ is frequently evaluated for upconversion applications. 11 Moreover, it has been showed a good efficient codoping-free upconversion process when irradiated with femtosecond sources.…”

mentioning

confidence: 99%

“…9 Most recently, it was proposed to apply the synthesis strategy adopted for organic-RE complex in the field of nanostructured systems with encouraging results. 13 This approach consists in improving the luminescence of Rare Earth metals by organic ligands at the surfaces.…”

mentioning

confidence: 99%

Luminescence enhancement by energy transfer in melamine-Y2O3:Tb3+ nanohybrids

Stagi

Chiriu

Ardu

et al. 2015

Journal of Applied Physics

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The phenomenon of luminescence enhancement was studied in melamine-Y2O3:Tb hybrids. Terbium doped Y2O3 mesoporous nanowires were synthesized by hydrothermal method. X-ray diffraction patterns and Raman scattering spectra testified the realization of a cubic crystal phase. Organic-inorganic melamine-Y2O3:Tb3+ hybrid system was successfully obtained by vapour deposition method. Vibration Raman active modes of the organic counterpart were investigated in order to verify the achievement of hybrid system. Photoluminescence excitation and photoluminescence spectra, preformed in the region between 250 and 350 nm, suggest a strong interaction among melamine and Terbium ions. In particular, a remarkable improvement of 5D4→ FJ Rare Earth emission (at about 542 nm) of about 102 fold was observed and attributed to an efficient organic-Tb energy transfer. The energy transfer mechanism was studied by the use of time resolved photoluminescence measurements. The melamine lifetime undergoes to a significant decrease when adsorbed to oxide surfaces and it was connected to a sensitization mechanism. The detailed analysis of time decay profile of Terbium radiative recombination shows a variation of double exponential law toward a single exponential one. Its correlation with surface defects and non-radiative recombination was thus discussed

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X-ray induced color change on dense yttria samples obtained by spark plasma sintering

Cited by 7 publications

References 49 publications

Al2O3–cBN composites sintered by SPS and HPHT methods

Al2O3–cBN composites sintered by SPS and HPHT methods

Structural, Electrical, and Mechanical Properties Investigation of Open-Cell Aluminum Foams Obtained by Spark Plasma Sintering and Replication on Polyurethane Template

Luminescence enhancement by energy transfer in melamine-Y2O3:Tb3+ nanohybrids

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