Grain growth suppression in alumina via doping and two-step sintering

Bodišová, Katarína; Galusek, Dušan; Švančárek, Peter; Pouchlý, Václav; Maca, Karel

doi:10.1016/j.ceramint.2015.05.162

Cited by 51 publications

(32 citation statements)

References 55 publications

(79 reference statements)

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“…In addition, as the sintering temperatures ( T 1 and T 2 ) during the TSS process increase, the grain sizes of samples slightly increase from 2.5 to 5.8 μm. These observations can be attributed to the TSS mechanism . In general, it has been proposed that the densification process of Mn‐Co‐Ni‐O ceramic microspheres is strongly dependent on the TSS process.…”

Section: Resultsmentioning

confidence: 93%

“…These observations can be attributed to the TSS mechanism. [17][18][19][20][21] In general, it has been proposed that the densifi cation process of Mn-Co-Ni-O ceramic microspheres is strongly dependent on the TSS process. Several factors affecting the densifi cation of ceramics are as follows: (1) The high starting temperature ( T 1 ) should be higher than the small 2016, 12, No.…”

Section: Resultsmentioning

confidence: 99%

“…Thus, one channel or nozzle is sufficient for ceramic formation. Moreover, further improvement in densification and grain growth of these ceramic materials can be ensured by the two step sintering (TSS) process . To date, however, the IJP and TSS techniques do not apply for fabrication of Mn‐Co‐Ni‐O ceramic microspheres materials.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Formation of Mn‐Co‐Ni‐O Nanoceramic Microspheres Using In Situ Ink‐Jet Printing: Sintering Process Effect on the Microstructure and Electrical Properties

Chen

Zhang

Yao

et al. 2016

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Mn-Co-Ni-O nanoceramic microspheres with high density, uniformity, and size tunability are successfully fabricated using in situ ink-jet printing and two step sintering (TSS) techniques. The microspheres, synthesized by an effective and facile reverse microemulsion method, consist of uncalcined Mn-Co-Ni-O nanocrystallines that show a well formed single tetragonal spinel phase and an average particle size distribution of ≈20 nm. The sintering behavior, microstructure, and electrical properties of the Mn-Co-Ni-O nanoceramic microspheres are systematically investigated and characterized. The results indicate that the sintered Mn-Co-Ni-O nanoceramic microspheres show high density and improved electrical properties. The highest R , B , E , and α values achieved at sintering temperature of 1150 °C are 4846.7 KΩ, 4320 K, 0.401 eV, and -5.24% K , respectively for these Mn-Co-Ni-O nanoceramic microspheres. Furthermore, the formation mechanism of uncalcined Mn-Co-Ni-O nanocrystallines and an analysis of the TSS procedure of the nanoceramic microspheres are discussed.

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Section: Resultsmentioning

confidence: 93%

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Formation of Mn‐Co‐Ni‐O Nanoceramic Microspheres Using In Situ Ink‐Jet Printing: Sintering Process Effect on the Microstructure and Electrical Properties

Chen

Zhang

Yao

et al. 2016

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“…The microstructure of pure alumina was slightly coarser than in doped samples, which confirmed, similarly to another additives segregating preferably at grain boundariese.g. Mg, Zr, Y, Er [12,22], the grain growth inhibiting effect of Eu doping. However, in terms of their influence on measured properties (RIT, photoluminescence, mechanical properties), all microstructures could be considered as similar.…”

Section: Microstructure and Real In-line Transmissionmentioning

confidence: 99%

Luminescent Eu3+-doped transparent alumina ceramics with high hardness

Drdlíková

Klement²,

Hadraba

et al. 2017

Journal of the European Ceramic Society

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The Eu 3+-doped transparent aluminas were prepared by wet shaping technique followed by pressure-less sintering and hot isostatic pressing. The effect of dopant amount on microstructure, real in-line transmission (RIT), photoluminescence (PL) properties, hardness and fracture behaviour was studied. The RIT decreased with increasing amount of the dopant. The PL emission spectra of Al2O3:Eu 3+ ceramics exhibited predominant red light emission with the highest intensity (under 394 nm excitation) for material containing 0.125 at.% of Eu 3+ and colour coordinates (0.645, 0.355) comparable with commercial red phosphors. The doping resulted in hardness increase from 26.1 GPa for undoped alumina to 27.6 GPa for Eu-doped sample. The study of fracture surfaces showed predominantly intergranular crack propagation micro-mechanism.

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“…In powder metallurgy processing, dopants are often used to influence the sintering behavior of powder compacts as well as to reduce grain boundary diffusivity and to improve the mechanical properties. These tailored properties can be achieved already at very low doping amounts, such as 0.1 mol.%, and have been widely demonstrated for aluminum oxide matrixes [ 33 , 34 ]. The tailoring of phase transformations can also be achieved by introducing certain cations within the host lattice.…”

Section: Introductionmentioning

confidence: 99%

Influence of Alumina Addition on the Optical Properties and the Thermal Stability of Titania Thin Films and Inverse Opals Produced by Atomic Layer Deposition

et al. 2021

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TiO2 thin films deposited by atomic layer deposition (ALD) at low temperatures (<100 °C) are, in general, amorphous and exhibit a smaller refractive index in comparison to their crystalline counterparts. Nonetheless, low-temperature ALD is needed when the substrates or templates are based on polymeric materials, as the deposition has to be performed below their glass transition or melting temperatures. This is the case for photonic crystals generated via ALD infiltration of self-assembled polystyrene templates. When heated up, crystal phase transformations take place in the thin films or photonic structures, and the accompanying volume reduction as well as the burn-out of residual impurities can lead to mechanical instability. The introduction of cation doping (e.g., Al or Nb) in bulk TiO2 parts is known to alter phase transitions and to stabilize crystalline phases. In this work, we have developed low-temperature ALD super-cycles to introduce Al2O3 into TiO2 thin films and photonic crystals. The aluminum oxide content was adjusted by varying the TiO2:Al2O3 internal loop ratio within the ALD super-cycle. Both thin films and inverse opal photonic crystal structures were subjected to thermal treatments ranging from 200 to 1200 °C and were characterized by in- and ex-situ X-ray diffraction, spectroscopic ellipsometry, and spectroscopic reflectance measurements. The results show that the introduction of alumina affects the crystallization and phase transition temperatures of titania as well as the optical properties of the inverse opal photonic crystals (iPhC). The thermal stability of the titania iPhCs was increased by the alumina introduction, maintaining their photonic bandgap even after heat treatment at 900 °C and outperforming the pure titania, with the best results being achieved with the super-cycles corresponding to an estimated alumina content of 26 wt.%.

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Grain growth suppression in alumina via doping and two-step sintering

Cited by 51 publications

References 55 publications

Formation of Mn‐Co‐Ni‐O Nanoceramic Microspheres Using In Situ Ink‐Jet Printing: Sintering Process Effect on the Microstructure and Electrical Properties

Formation of Mn‐Co‐Ni‐O Nanoceramic Microspheres Using In Situ Ink‐Jet Printing: Sintering Process Effect on the Microstructure and Electrical Properties

Luminescent Eu3+-doped transparent alumina ceramics with high hardness

Influence of Alumina Addition on the Optical Properties and the Thermal Stability of Titania Thin Films and Inverse Opals Produced by Atomic Layer Deposition

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