| 1. |
- Fu, Le, et al.
(författare)
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Liquid-phase sintering of ZrO2-based nanocrystalline glass-ceramics achieved by multielement co-doping
- 2023
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Ingår i: Journal of The American Ceramic Society. - : John Wiley & Sons. - 0002-7820 .- 1551-2916. ; 106:4, s. 2702-2715
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Tidskriftsartikel (refereegranskat)abstract
- Liquid-phase sintering (LPS) is an effective pathway to assist the densification of ceramics. However, it has seldom been used to densify glass-ceramics. In the present study, a multielement co-doping strategy has been utilized to achieve LPS of a ZrO2-SiO2 nanocrystalline glass-ceramic. Compared with undoped samples densified by solid-state sintering, doping of equimolar Al, Y, and Ca promoted the densification of the glass-ceramic at lower temperatures with a faster densification rate. Ternary doping enhanced coarsening of ZrO2 nanocrystallites during sintering and annealing. The distribution of dopants was carefully observed with X-ray energy-dispersive spectrometry technique in scanning electron transmission microscopy mode. Results showed that the three dopants showed different distribution behaviors. After sintering, Y dopants were predominately distributed in ZrO2 nanocrystallites, whereas parts of Al and Ca dopants were distributed in ZrO2 nanocrystallites and part of them co-segregated at the ZrO2/SiO2 heterointerfaces. Meanwhile, the segregation of Ca dopant at some intergranular films among ZrO2 nanocrystallites was observed. Redistribution of dopants did not occur during annealing.
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| 2. |
- Fu, Le, et al.
(författare)
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Structural integrity and damage of glass-ceramics after He ion irradiation : Insights from ZrO2-SiO2 nanocrystalline glass-ceramics
- 2023
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Ingår i: Journal of the European Ceramic Society. - : Elsevier. - 0955-2219 .- 1873-619X. ; 43:6, s. 2624-2633
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Tidskriftsartikel (refereegranskat)abstract
- Developing new radiation-resistant materials and understanding the structural damages caused by radiation are persistent goals of material scientists. Here, we report on the structural integrity and damage to ZrO2-SiO2 nanocrystalline glass-ceramics after radiation with 1.4 MeV He ions at three different fluences: 1.0 x 1016 ions/ cm2 (low), 5.0 x 1016 ions/cm2 (moderate), and 1.0 x 1017 ions/cm2 (high) at 500 degrees C. Grazing incident X-ray diffraction shows the tetragonal-ZrO2 to monoclinic-ZrO2 phase transformation induced by microstrain from the irradiation. The addition of yttrium indicated tetragonal-ZrO2 stabilization effect during irradiation. The irra-diated glass-ceramics show a Raman signal-enhancement effect probably related to the electronic structure changes of the amorphous SiO2 component in the glass-ceramics. The formation of microcracks and lattice de-fects within ZrO2 nanocrystallites is the main structural damage caused by irradiation. There was no observable amorphization of ZrO2 nanocrystallites due to irradiation. No obvious He bubbles were detected, either. The formation of microcracks results in a decrease of in the nanohardness of the glass-ceramics. The results provide fundamental experimental data to understand the structural integrity and damage caused by radiation, which could be useful to design radiation-resistant nanocrystalline glass-ceramics for extremely radioactive environments.
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| 3. |
- Wang, Bohan, et al.
(författare)
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Low-temperature and flexible strategy to in-situ fabricate ZrSiO4-based ceramic composites via doping and tuning solid-state reaction
- 2023
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Ingår i: JOURNAL OF ADVANCED CERAMICS. - : Tsinghua University Press. - 2226-4108 .- 2227-8508. ; 12:6, s. 1238-1257
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Tidskriftsartikel (refereegranskat)abstract
- Synthetic zircon (ZrSiO4) ceramics are typically fabricated at elevated temperatures (over 1500 degrees C), which would lead to high manufacturing cost. Meanwhile, reports about preparing ZrSiO4-based ceramic composites via controlling the solid-state reaction between zirconia (ZrO2) and silica (SiO2) are limited. In this work, we proposed a low-temperature strategy to flexibly design and fabricate ZrSiO4-based ceramic composites via doping and tuning the solid-state reaction. Two ceramic composites and ZrSiO4 ceramics were in-situ prepared by reactive fast hot pressing (FHP) at approximately 1250 degrees C based on the proposed strategy, i.e., a ZrSiO4-SiO2 dual-phase composite with bicontinuous interpenetrating and hierarchical microstructures, a ZrSiO4-ZrO2 dual-phase composite with a microstructure of ZrO2 submicron- and nano-particles embedded in a micron ZrSiO4 matrix, and ZrSiO4 ceramics with a small amount of residual ZrO2 nanoparticles. The results showed that the phase compositions, microstructure configurations, mechanical properties, and wear resistance of the materials can be flexibly regulated by the proposed strategy. Hence, ZrSiO4-based ceramic composites with different properties can be easily fabricated based on different application scenarios. These findings would offer useful guidance for researchers to flexibly fabricate ZrSiO4-based ceramic composites at low temperatures and tailor their microstructures and properties through doping and tuning the solid-state reaction.
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