المؤلفون: Sedano, M.¹ (AUTHOR), Durán, A.¹ (AUTHOR), Mather, G.C.¹ (AUTHOR), Fernández, J.² (AUTHOR), Balda, R.^3,4 (AUTHOR), Pascual, M.J.¹ (AUTHOR) mpascual@icv.csic.es

المصدر: Ceramics International. Jul2024:Part B, Vol. 50 Issue 13, p23839-23846. 8p.

مصطلحات موضوعية: *GLASS-ceramics, *TRANSPARENT ceramics, *PALETTE (Color range), *DOPING agents (Chemistry), *EXCITATION spectrum, *TRANSMISSION electron microscopy, *OXIDATION-reduction reaction

مستخلص: Eu/Ag-co-doped transparent oxyfluoride glass-ceramics based on LaF 3 have been obtained by melt-quenching followed by structural analysis employing X-ray diffraction and transmission electron microscopy. Absorption spectra showed only Eu3+ ion transitions, irrespective of the presence of silver or the atmosphere used in the preparation. Excitation spectra obtained by collecting luminescence at 437 nm (Eu2+) and 612 nm (Eu3+) indicated the partial reduction of Eu3+ to Eu2+. As a consequence, by tuning the excitation wavelength, a variety of emission spectra are obtained, highlighting the coexistence of Eu2+ and Eu3+ ions, with the emission dominance of the type of ion dependent on the excitation wavelength. The presence of Ag and the atmosphere used during sample preparation affected the intensity of certain emissions, indicating the presence of oxidation-reduction reactions. Chromaticity diagrams illustrating the changes in colour coordinates corresponding to variations in the excitation wavelength showed a range of colours from red to blue, including purple-blue tones. [ABSTRACT FROM AUTHOR]

المؤلفون: Liu, Xinwen¹ (AUTHOR), Mei, Bingchu¹ (AUTHOR) bcmeilab@163.com, Tan, Guolong¹ (AUTHOR)

المصدر: Journal of the European Ceramic Society. Jul2024, Vol. 44 Issue 8, p4975-4984. 10p.

مصطلحات موضوعية: *CERAMICS, *TRANSPARENT ceramics, *PHOTON upconversion, *LUMINESCENCE, *VISIBLE spectra, *MICROSTRUCTURE, *KEYWORD searching

مستخلص: Fluoride-upconversion transparent ceramic materials doped with Er ions have attracted extensive interest due to their higher stability, lower phonon energy, and higher upconversion efficiency. xEr:Sr 5 (PO 4) 3 F (S-FAP) (x=0.5–5 at%) transparent ceramics have been synthesized by hot pressing sintering in this work, and the maximum optical transmittance of the sample reached 74.52 and 82.45% at 500 and 1000 nm, respectively. The XRD results of the powder and ceramic samples were consistent with the diffraction characteristics of the hexagonal S-FAP crystal structure. The SEM and TEM images of powder revealed that the morphology of the sample was composed of mostly rice grains with a diameter of around 20 nm. The XPS and EDS results confirmed the presence of Er3+ and the uniform distribution of Er elements. The thermally etched surface and cross section of ceramics revealed residual pores as the most important scattering source, and the SEM images of the ceramics show that Er doping can obviously promote the growth of the average grain size of S-FAP transparent ceramics. Furthermore, the upconversion luminescence characteristics and fluorescence lifespan of S-FAP transparent ceramics with varied Er doping concentrations were examined, as well as the upconversion luminescence process. The findings in this work indicate that Er:S-FAP transparent ceramics can be employed as a potential upconversion fluorescent material in display technology, biomedicine, temperature sensing, and other applications. • The xEr:S-FAP (x=0–0.05) transparent nanostructured ceramics with highly optical quality were prepared by hot-pressed sintering for the first time. • The microstructural characteristics, upconversion luminescence property, and mechanism of as-synthesized xEr:S-FAP transparent ceramics were investigated for the first time. • The wide visible light spectrum from red light to green light was achieved by changing the doping amount of Er3+ from 0.5 to 5 at%. [ABSTRACT FROM AUTHOR]

المؤلفون: Zhu, Dan^1,2 (AUTHOR), Zhou, Jiacheng^1,2 (AUTHOR), Zheng, Jianxin^1,2 (AUTHOR), Huo, Tongguo^1,2 (AUTHOR), Dai, Yu^1,2,3 (AUTHOR) daiyu@vip.163.com, Wu, Jian^1,2,3 (AUTHOR) wujian@ncu.edu.cn

المصدر: Ceramics International. Jul2024:Part A, Vol. 50 Issue 13, p22373-22380. 8p.

مصطلحات موضوعية: *COAGULATION, *TRANSPARENT ceramics, *MALEIC anhydride, *SINTERING, *SLURRY, *NITRIDATION, *GELATION

مستخلص: Aluminum oxynitride (AlON) exhibits excellent mechanical properties and good optical transparency in the ultraviolet to near-infrared range and can be used in military and civilian fields. However, the troublesome molding of AlON, especially for complex shapes, limits its promotion and application. Therefore, transparent AlON ceramics with complex morphologies were prepared for the first time by a novel spontaneous coagulation casting (SCC) and pressureless sintering method. In this study, we report a simple carbothermal reduction and nitridation (CRN) method for synthesizing high-purity AlON powder, which is especially suitable for wet casting without anti-hydration treatment. The dispersion and gelation behavior of AlON slurries by isobutene maleic anhydride copolymer (Isobam104) and tetramethylammonium hydroxide (TMAH) were extensively investigated. With the addition of 0.9 wt% Isobam104 and 15 mL/L TMAH, the AlON slurries can achieve a solids loading of up to 45 vol% with the lowest viscosity (460.4 mPa·s-10 r/min) and the AlON green body is free of cracks and deformation during drying and demolding processes. Finally, the AlON green bodies with square and polygonal irregular morphologies were fabricated via a simple SCC method. High transparent AlON ceramics of a maximum transmittance up to 77.3% at 2000 nm and 72.2% at 632 nm were obtained by pressureless sintered at 2000 °C for 6 h. The SCC method has great potential in preparing ceramics with controllable shapes. [ABSTRACT FROM AUTHOR]

المؤلفون: Aminaka, Kohei¹ (AUTHOR), Tatami, Junichi² (AUTHOR) tatami-junichi-xv@ynu.ac.jp, Iijima, Motoyuki² (AUTHOR), Ito, Akihiko² (AUTHOR), Matsumoto, Shogen¹ (AUTHOR), Takahashi, Takuma^2,3 (AUTHOR), Ohji, Tatsuki^2,4 (AUTHOR)

المصدر: International Journal of Applied Ceramic Technology. Jul2024, Vol. 21 Issue 4, p2671-2677. 7p.

مصطلحات موضوعية: *TRANSPARENT ceramics, *FUSION reactors, *NUCLEAR facility decommissioning, *SCINTILLATORS, *RARE earth ions, *OPTICAL materials, *RARE earth metal alloys

مستخلص: The high durability under harsh environment including high temperature, high humidity, and high radiation is required for scintillators used for decommissioning of nuclear facilities and radiation monitoring in nuclear fusion reactors. α‐SiAlON ceramics are highly potential for such scintillators because of their thermal and mechanical durability and luminescence corresponding to doped rare‐earth ion. In this study, scintillation properties of transparent Lu‐α‐SiAlON:Ce3+ ceramics were investigated for the first time. Lu‐α‐SiAlON:Ce3+ showed the scintillation responses to α‐rays and X‐rays. The α‐rays‐induced scintillation decay curve consists of two components whose decay time are 48 and 652 ns. The faster decay component most presumably results from 4f‐5d transition of Ce3+, whereas the origin of the slower one is unclear but may be defects in α‐SiAlON. The light yield of the Lu‐α‐SiAlON:Ce3+ ceramics was 1300 photons 5.5 MeV−1. [ABSTRACT FROM AUTHOR]

المؤلفون: Lu, Kailei^1,2 (AUTHOR), Guan, Mengqiu² (AUTHOR), Xie, Yuhong² (AUTHOR), Han, Wenhan² (AUTHOR), Ye, Yucheng³ (AUTHOR), Li, Zijie² (AUTHOR), Wang, Guixin¹ (AUTHOR), Qi, Jianqi² (AUTHOR) qijianqi@scu.edu.cn, Lu, Tiecheng² (AUTHOR) lutiecheng@scu.edu.cn

المصدر: Advanced Optical Materials. 6/26/2024, Vol. 12 Issue 18, p1-11. 11p.

مصطلحات موضوعية: *TRANSPARENT ceramics, *THERMOMETRY, *EXCITED states, *TERBIUM, *POPULATION dynamics, *LUMINESCENCE

مستخلص: Temperature‐responsive dynamics of excited‐state population in terbium (Tb) ions may open the door for the advancement of high‐performance photothermal feedback windows. However, obtaining robust luminescence and superior transparency in Tb‐doped ceramics continues to pose a formidable challenge, leaving them far away from photonic application. Here, to fill this important gap, the demonstration of Tb doped transparent ceramics for luminescent thermometric windows is reported. Y2Zr2O7:Tb (YZO:Tb) ceramics are used as an illustrative example. After a sequence of thermal treatments, the defect centers F/F+ and defect clusters [TbY4+−O2−−TbY4+$Tb_{\mathrm{Y}}^{{{4}^ + }} - {{O}^{2 - }} - Tb_{\mathrm{Y}}^{{{4}^ + }}$] and [TbY4+−e•$Tb_{\mathrm{Y}}^{{{4}^ + }} - {{e}^ \bullet }$] in these YZO:Tb transparent ceramics are eliminated, resulting in a notable enhancement of their in‐line transmittance from 71% to 76%, making it close to the theoretical limit. Moreover, the corresponding photoluminescence increased significantly, reaching a factor of 296 times. Furthermore, a temperature feedback window is designed using the excitation intensity ratio (EIR) or single‐band luminescence intensity ratio (SBLIR) mode, which presents high sensitivity (1.04%) and high repeatability (98%). This work not only provides a paradigm in the application of the Tb doped transparent ceramics for temperature sensing windows, but also suggests a pathway to build efficient thermometers based on excited state population deployment in window systems. [ABSTRACT FROM AUTHOR]

المؤلفون: Song, Zhiqiang¹ (AUTHOR), Zhang, Zhuo² (AUTHOR), Yu, Yirong² (AUTHOR), Lin, Dabin² (AUTHOR) dabinlin@xatu.edu.cn

المصدر: International Journal of Smart & Nano Materials. Jun2024, Vol. 15 Issue 2, p296-311. 16p.

مصطلحات موضوعية: *ELECTRIC properties, *TRANSPARENT ceramics, *DOPING agents (Chemistry), *FERROELECTRIC ceramics, *PHASE transitions, *PERMITTIVITY, *TRANSITION temperature, *ELECTROMAGNETIC interference

مستخلص: Ferroelectric ceramics display a remarkable photostriction effect, which could facilitate the prevention of electromagnetic interference and promote the integration and miniaturization of actuator systems, indicating potential applications in glimmer sensors. In this work, highly transparent La-doped 0.9Pb(Mg1/3Nb2/3)O3-0.1PbTiO3 (0.9PMN–0.1PT) ceramics were synthesized using a solid-state reaction method in an oxygenated atmosphere. XRD and SEM were used to analyze the phase structure of the dense samples, which displayed a pure perovskite structure, with no trace of a pyrochlore phase. With La doping, the phase transition temperature shows a decreasing trend, and its dielectric constant could reach up to 20,000. The P-E loop of the samples was gradually refined into a straight line with an increase in the doping amount. After La doping, the transparency of the 0.9PMN–0.1PT ceramics was significantly enhanced and reached up to 61% at the near-infrared band. Finally, the photogenerated voltage and deformation of the La-doped 0.9PMN–0.1PT ceramics were investigated under ultraviolet light of various intensities. After 20 s of irradiation at an intensity of 800 mW/cm2, the maximum voltage and deformation, with values of 40 V and 250 nm, respectively, were both found in the 1%La-doped 0.9PMN–0.1PT ceramics. [ABSTRACT FROM AUTHOR]

المؤلفون: Liu, Xinwen¹ (AUTHOR), Mei, Bingchu¹ (AUTHOR) bcmeilab@163.com, Tan, Guolong¹ (AUTHOR)

المصدر: Ceramics International. Jun2024:Part A, Vol. 50 Issue 11, p18380-18390. 11p.

مصطلحات موضوعية: *TRANSPARENT ceramics, *HOT pressing, *SINTERING, *LITHIUM fluoride, *CERAMICS, *DOPING agents (Chemistry), *CRYSTAL grain boundaries

مستخلص: Transparent hexagonal 2 at.% Yb:Sr 5 (PO 4) 3 F (S -FAP) ceramics were effectively fabricated by hot pressing the coprecipitated powder employing LiF as the sintering additive. The effects of LiF doping levels (0–0.5 wt%) and sintering temperature (820–940 °C) on microstructural development and optical characteristics of samples were examined. The results showed that the addition of LiF and the evaluated sintering temperature accelerated the grain development and densification process of Yb:S-FAP ceramics. Also, the full densification process of low-doped LiF ceramic samples was found to be strongly dependent on the reduced sintering temperature. For the Yb:S-FAP transparent ceramic sintered at the lowest temperature of 850 °C than previously reported with 0.1 wt% LiF, which have an optical in-line transmittance of 59.7% and 79.66% at 500 and 1100 nm respectively. The corresponding scattering sources of ceramic samples were analyzed by the surface SEM of different magnification at different LiF doping concentrations, and residual LiF, residual porosity, and grain boundary scattering were considered to be the main scattering sources. The spectral results showed that the LiF-doped Yb:S-FAP transparent ceramics had a wide absorption peak at 975 nm with the full width at half maximum (FWHM) of 15 nm and possessed a fluorescence lifetime of 1.12 ms. [ABSTRACT FROM AUTHOR]

المؤلفون: Zhang, Lixuan^1,2 (AUTHOR), Starobor, Aleksey V.^3,4 (AUTHOR), Hu, Dianjun^1,2 (AUTHOR), Li, Xiao^1,5 (AUTHOR), Hu, Chen¹ (AUTHOR), Wu, Lexiang¹ (AUTHOR), Palashov, Oleg V.^3,4 (AUTHOR), Li, Jiang^1,2 (AUTHOR) lijiang@mail.sic.ac.cn

المصدر: Journal of the American Ceramic Society. Jun2024, Vol. 107 Issue 6, p3653-3658. 6p.

مصطلحات موضوعية: *TRANSPARENT ceramics, *ISOSTATIC pressing, *HOT pressing, *CERAMICS, *TERBIUM, *MICROSTRUCTURE

مستخلص: Tb3Al5O12 (TAG) ceramics with high optical quality were fabricated successfully by a solid‐state reaction method combined with hot isostatic pressing (HIP) post‐treatment. The microstructure, optical transmittance, Verdet constant, and thermo‐optical properties were investigated. The obtained TAG ceramics showed a dense microstructure, and the in‐line transmittance reached 82.8% at 1070 nm after laser‐grade polishing. The Verdet constant of TAG ceramics was measured to be 50.9 rad·T1·m−1 at 1070 nm, which is higher than that of commercial Tb3Ga5O12 crystals. The Faraday isolator based on TAG ceramics can provide an isolation ratio of 30 dB with a laser power of more than 1 kW. With excellent optical quality, high Verdet constant, and maximum working power, TAG transparent ceramics are promising for applications of kilowatt‐level Faraday isolators. [ABSTRACT FROM AUTHOR]

المؤلفون: Feng, Yagang^1,2,3 (AUTHOR), Liu, Ziyu^1,4 (AUTHOR), Toci, Guido⁵ (AUTHOR), Pirri, Angela⁶ (AUTHOR), Patrizi, Barbara⁵ (AUTHOR), Vannini, Matteo⁵ (AUTHOR), Hreniak, Dariusz⁷ (AUTHOR), Li, Jiang^1,2 (AUTHOR) lijiang@mail.sic.ac.cn

المصدر: Journal of the American Ceramic Society. Jun2024, Vol. 107 Issue 6, p4134-4146. 13p.

مصطلحات موضوعية: *TRANSPARENT ceramics, *YTTERBIUM, *THULIUM, *ACTIVE medium, *CERAMICS, *ISOSTATIC pressing, *LASERS, *MICROSTRUCTURE

مستخلص: Highly transparent 10 at.% Yb:GdxY3−xAl5O12 (x = 0.3, 0.5, and 0.7) ceramics were successfully fabricated by vacuum solid‐state reactive sintering at 1800°C for 20 h combined with hot isostatic pressing posttreatment at 1700°C for 3 h under 176 MPa pressure in Ar atmosphere. The in‐line transmittances of these ceramics with the thickness of 2.5 mm are 84.4%, 84.0%, and 83.5% at 1100 nm for x = 0.3, 0.5, and 0.7, respectively. The relationships of the Gd3+ content among the phase, microstructures, spectral, and laser properties of the Yb:GdxY3−xAl5O12 ceramics were elucidated in detail. The introduction of Gd3+ has a little influence on the crystal field strength of the Yb3+ sites in GdxY3−xAl5O12. The absorption, emission spectra, and fluorescence lifetime of the Yb3+ in these ceramics are similar, close to 10 at.% Yb:YAG ceramics. Quasi‐continuous wave laser outputs of the ceramics were also achieved. The maximum laser output powers are 7.8, 7.7, and 6.6 W with the corresponding slope efficiency as 46.2%, 44.7%, and 39.2% for x = 0.3, 0.5, and 0.7, respectively. The 7.8 W laser output power is the highest value achieved so far for the Yb:GdYAG ceramics, to the best of our knowledge. The previous discussions show that not all the mixed garnets could enhance full width at half maximum of absorption and emission peaks for the active ions; however, the Yb:GdYAG ceramics are still excellent laser gain media. [ABSTRACT FROM AUTHOR]

المؤلفون: Luo, Haoming^1,2 (AUTHOR), Han, Dan¹ (AUTHOR), Zhang, Jian^1,2 (AUTHOR) jianzhang@mail.sic.ac.cn, Wang, Shiwei^1,2 (AUTHOR), Liu, Peng³ (AUTHOR)

المصدر: Journal of the European Ceramic Society. Jun2024, Vol. 44 Issue 6, p4216-4224. 9p.

مصطلحات موضوعية: *TRANSPARENT ceramics, *CERAMICS, *ISOSTATIC pressing, *CRYSTAL grain boundaries, *HOT pressing, *OPTICAL properties

مستخلص: In this paper, YOF was used as the sintering additive for obtaining MgAl 2 O 4 transparent ceramics with excellent optical properties. It is found that YOF enhances the densification of MgAl 2 O 4 ceramics. In addition, YOF can effectively suppress grain growth in the final stage because of the reduction of grain boundary energies and the pinning effect at the grain boundary region during the hot isostatic pressing (HIPing) process. Nevertheless, it is important to carefully control the content of YOF. Although the formation of a low amount of Y 3 Al 5 O 12 (YAG) is advantageous because its grains are doing the pinning effect at the grain boundary, an excessive amount is not desired as it is likely to cause scattering. After optimizing the YOF content and sintering temperature, the final sample (4 mm thick after polishing) with 0.01 wt% YOF HIPed at 1550 °C is obtained, showing the high in-line transmittance of 82.6% at 400 nm and high flexural strength of 271.6 MPa. [ABSTRACT FROM AUTHOR]