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Numerical simulations of the evolution of mobile and immobile dislocations in ceramics under applied pressure in dry pressing at a relatively low temperature are performed in order to study the possibility of production of all-dislocation-ceramics of solid electrolytes, which are expected to have extremely high ionic conductivity without dendrite formation because the diameter of a dislocation pipe is considerably larger than the distance between neighboring dislocations. The present numerical simulations are only for the densification process by plastic deformation of grains under high pressure under the assumption that the compaction of particles by their rearrangement is completed beforehand. By the plastic deformation, new dislocations are generated inside the grains. The required total dislocation density of about 1017 m−2 seems to be achievable under some conditions of dry pressing according to the present numerical simulations. Very short ultrasound irradiation at the beginning of the dry pressing sometimes considerably increases the dislocation density, while for other cases, it even considerably decreases the dislocation density due to enhanced annihilation of mobile dislocations by ultrasound. [ABSTRACT FROM AUTHOR]

Cubic‐phase magnesium‐aluminum spinel (MAS) has attractive optical, mechanical, and thermal properties and has been widely used as transparent ceramics in a number of applications. However, the processing of MAS transparent ceramics typically requires pre‐sintering and hot isostatic pressing (HIP) both at very high temperatures (e.g., above 1600°C) over an extended time, which coarsens the microstructure thus impairing mechanical properties. There is an urgent need to lower the sintering temperature while maintaining high optical transparency. Here we reported new progress in combining two‐step sintering in the pressureless pre‐sintering step and low‐temperature HIP in the post‐treatment step, using high‐quality green bodies produced by pressure filtration. With this strategy, high‐quality MAS transparent ceramics are delivered. The main benefits include 200°C lower HIP temperature, a 33% smaller average grain size of 350 nm, and a higher hardness of 14.8 GPa. Such a method could be extended to many other transparent ceramics. [ABSTRACT FROM AUTHOR]

Y 2 O 3 ceramic fabricated by Spark Plasma Sintering (SPS) has the potential to have fine grain sizes and rapid fabrication. Carbon contamination, however, is noted for oxide materials sintered via SPS due to the graphite tooling. In the present work, a variety of 25–50 μm thick metallic foils are utilized to prevent carbon contamination in the final specimen. The carbon contamination appeared as carboxylate absorption bands between 6 and 7 μm wavelength region. Ta foil was found to be superior to all other metals as a carbon blocker for improved transmission of the ceramic in both the visible and the infrared (IR). Inexpensive and thin foils of metals such as Ti and Zr proved suitable for IR transmission in materials where visible transmission is limited by structure or scattering from multiple phases such as 3YSZ or Y 2 O 3 -MgO composites. [ABSTRACT FROM AUTHOR]

When preparing aluminum oxynitride (AlON) transparent ceramics from Al 2 O 3 -AlN slurries by direct ink writing (DIW), green bodies need long drying duration to guarantee uniform water evaporation but AlN hydration will happen, creating extra alumina content and deteriorating the optical properties of AlON. Being capable of dissolving a portion of Al 2 O 3 , MgAl 2 O 4 was doped to prepare AlON transparent ceramics through reactive sintering using DIW technology. With 79 wt% solid-content aqueous slurries, AlON gradually becomes single phase with densities around 3.69 g/cm3 after MgAl 2 O 4 content and sintering temperature regulating, resulting in a substantial enhancement in optical transmittance. Through transmission electron microscopy analysis, MgAl 2 O 4 helps reduce the internal stress in AlON lattice, diminishing lattice distortion and enhancing transmittance. However, MgAl 2 O 4 addition also results in grain size increase and decreases mechanical properties of AlON. This study provides a new approach to solve AlN hydration when preparing AlON transparent ceramics by DIW from Al 2 O 3 -AlN aqueous slurries. [ABSTRACT FROM AUTHOR]

In-situ glass crystallization provides a unique platform to create hybrid materials with improved performances for emerging photonics applications. Here we report the design of a glass ceramic embedded with Ca 2 MgSi 2 O 7 :Eu2+ akermanite under the guideline of CaO-MgO-SiO 2 phase equilibrium. The growth of the akermanite from ultrasmall spherical nanoparticles to highly orientated dendrites is experimentally controlled. Notably, the resulting orientated dendritic glass ceramic achieves high crystalline up to 90.1 % due to the homogeneous congruent crystallization, and transparency as result of the reduced light scattering. Thanks to metastable electric carriers trapping center with ideal trap depth of 0.52–0.70 eV, and sunlight excitable properties of the crystallized akermanite, as revealed by thermoluminescence technique, the developed glass ceramic exhibits impressive optical storage capability. This highly crystalline glass ceramic coupling with excellent optical properties and chemical/physical stability is of particular interests for a wide range of applications in the safety field and high security fluorescent anti-counterfeiting. [Display omitted] [ABSTRACT FROM AUTHOR]

1.0% Nd-doped BaCl2 transparent ceramic and single crystal samples were respectively prepared by spark plasma sintering and the vertical Bridgman-Stockbarger method to compare their optical and scintillation properties. The photoluminescence quantum yield of the crystal sample was 5.4% under 580 nm excitation, whereas that of the ceramic sample was below the detection limit of the device. In the scintillation spectra, multiple emission peaks derived from 4f-4f transitions of Nd3+ were observed in the 530-1330 nm range for both samples. For the dose rate response function, the lower detection limits of the ceramic and crystal samples were 0.03 and 0.003 Gy/h, respectively. Our samples had better detection limits than previously reported values of Nd:CsI (0.06 Gy/h) and Nd:CaWO4 (0.06 Gy/h) single crystals. [ABSTRACT FROM AUTHOR]

Polycrystalline magnesium aluminate spinel, or simply spinel, with near theoretical density is a transparent ceramic material with multiple applications in extreme environmental conditions, which require an enhanced fracture toughness. For this reason, in this study, the effect of 500 ppm doping level of calcium (Ca) and yttrium (Y) on the segregation behavior and mechanical properties of spinel was quantitatively investigated. Calcium and yttrium doping reduced the grain-boundary plane anisotropy for grain boundaries with rotations about the [111] axis. More tilt boundaries and fewer twist boundaries were found in the doped samples compared to the undoped condition. Direct observations by high-angle annular dark-field scanning transmission electron microscopy (HAADF-STEM) imaging revealed that yttrium atoms preferentially occupy aluminum sites at grain boundaries in spinel. Quantitative electron energy-loss spectrometry (EELS) analysis in the vicinity of grain boundaries indicated that calcium atoms preferentially occupy magnesium sites in the Ca-doped spinel samples and confirmed the substitution of aluminum by yttrium atoms in the Y-doped sample. Quantitative X-ray energy-dispersive spectrometry (XEDS) analysis employing the ζ-factor method indicated that the maximum segregation levels at grain boundaries were 0.8 ± 0.1 calcium atoms/nm2 (0.23 ± 0.03 monolayers) and 2.4 ± 0.06 yttrium atoms/nm2 (0.45 ± 0.11 monolayers). Enhanced indentation fracture toughness was found in samples with calcium and yttrium doping compared to undoped spinel. The enhanced fracture toughness in Ca- and Y-doped spinel samples, in comparison with undoped spinel, was primarily attributed to more pronounced crack deflections and a more tortuous crack path. [ABSTRACT FROM AUTHOR]

The influence of the content and ratio of MgO and CaO sintering additives on the optical properties of YAG:Cr3+ and YAG:Cr4+ ceramic materials was investigated. All samples showed high transparency at 1100 nm (more than 80%). However, in the approx. 340 nm region, the light transmittance values of the samples decreased with increasing amounts of Ca2+ or Mg2+ ions. The most intense absorption in the range of 750 – 1100 nm after annealing in air was observed in the samples containing the highest value of sintering additives. The absorption of Cr4+ cations increased with the increase of Ca/Mg content. The optimum CaO content among the investigated samples was 0.12 wt.%. Above this value, additional absorption was observed due to the formation of microdefects. The data obtained by scanning electron microscopy showed that the ceramic samples had a granular structure with grain size ranging from 1 to 10 μm. There were no significant differences in the microstructure depending on the content and type of sintering additives. [ABSTRACT FROM AUTHOR]

In recent years, transparent terbium gallium garnet (TGG) ceramics have garnered significant interest for their application in high‐power Faraday isolators. However, challenges in achieving high transparency have led researchers to explore the addition of various sintering aids as a key strategy to enhance the optical quality of TGG ceramics. Through this work, the effect of germanium (Ge) addition on the microstructure and optical transparency of TGG magneto‐optical ceramics was investigated. TGG powders were synthesized by the co‐precipitation method, and the source Ge was Ge ethoxide added through a ball‐milling step. Transparent TGG ceramics were prepared by air pre‐sintering combined with hot isostatic pressing post‐treatment and subsequent annealing. The ceramics containing 200 ppm Ge exhibit optimal transmittance of 81.3% at 1064 nm (a value of theoretical transmittance), the Verdet constant was −133.0 rad·T−1·m−1 at 633 nm. When the addition of Ge reaches 600 ppm, a secondary phase can be observed on the surface of ceramic. Subsequently, TGG ceramics prepared from 1425°C to 1500°C with 200 ppm of Ge were analyzed, which revealed that the optimal pre‐sintering temperature is 1450°C. [ABSTRACT FROM AUTHOR]

Gallium oxide (Ga2O3) has attracted much attention due to its promising applications in optical and electronic devices, while it is difficult to fabricate high‐quality Ga2O3 transparent ceramics because of the non‐cubic crystal structure. In this work, fully densified undoped and rare earth (RE = Tb, Dy. Er)‐doped Ga2O3 transparent ceramics were successfully fabricated by using spark plasma sintering (SPS) and co‐precipitated ceramic powders. Both the powders and ceramics showed pure monoclinic β‐ Ga2O3 crystal structure and unique orientation. After sintering by SPS for 30 min, all the ceramics reached a relative density higher than 99.21%. The total transmittance of RE‐doped Ga2O3 transparent ceramics ranges from 60% to 69% originating from the oriented and dense microstructures. The photoluminescence spectra and fluorescence lifetime of RE‐doped Ga2O3 transparent ceramics confirm characteristics of energy transfers corresponding to Tb3+, Dy3+, or Er3+ ions in the visible and NIR spectral region. This study demonstrates that oriented RE‐doped Ga2O3 transparent ceramics have great potential to be used in various optical applications. [ABSTRACT FROM AUTHOR]

Glass is one of the oldest and most versatile manmade materials and has been used for centuries. One of the areas of significant research and progress is that of high-mechanical-resistance glass. Several processes can be used to maximize the mechanical strength of glasses, namely thermal or chemical treatments. Glass ceramics, obtained through controlled crystallization, can enhance the mechanical properties of these materials and, as long as the crystals remain small enough, transparent glass ceramics can be obtained. On the other hand, ion exchange can strengthen the glass surface and reduce failure. As a result, ceramization followed by ion exchange can further enhance the mechanical characteristics of the parent glass. Aluminosilicate glasses and glass ceramics are known to present excellent transparency and chemical durability, plus good mechanical behavior; therefore, a lithium aluminosilicate glass composition was studied in order to obtain transparent glass ceramics, followed by an ion exchange process, and its mechanical properties were studied. Transparent glass ceramics were obtained, with an increase of ~15% in hardness over the parent glass. The glass ceramics were then subjected to an ion exchange treatment in a KNO3 bath, in order to further enhance the mechanical properties, without hindering the optical transmittance. The combination of heat treatment and chemical treatment resulted in a cumulative hardness increase of ~25%, from 620 ± 10 HV, for the as-cast glass and from 773 ± 23 HV for the ion-exchanged glass ceramic. Regarding the indentation fracture toughness, values obtained for the glass ceramics were similar to those obtained for the cast glass, yielding no noticeable change. Indentation fracture toughness increased after the ion exchange treatment of the glass ceramic, since a much higher load was necessary to obtain a measurable indentation, indicating higher indentation fracture strength. [ABSTRACT FROM AUTHOR]

Transparent ceramics nowadays finds applications in infrared windows, lamps covers, optoelectronic devices, smart phone screens and especially as host materials for solid-state lasers. One such ceramic material, Y2O3 was considered in the present investigation and the effect of neodymium (Nd) and erbium (Er) at different concentrations (0.5, 1.0, 1.5 and 2.0 at%) was studied. Transparent ceramic pellets were synthesized by co-precipitation method, sintered at high vacuum and finally polished. Structural characterizations confirmed the presence of cubic phase and scanning electron micrographs established the compactness of the samples with no secondary phase. The ceramics were found to have good transparency around 75%. Refractive index measurements showed least absorption at higher wavelengths which ensures good transmission properties. The upconversion and downconversion mechanisms are discussed in detail with varying Er concentration for different excitation wavelengths. The observations clearly indicate green and red emissions which ensure the effective utilization of these transparent ceramics as dual mode emitters. [ABSTRACT FROM AUTHOR]

(Sr0.97Eu0.01Dy0.02)Al2O4 persistent luminescence (PersL) ceramics were fabricated by solid‐state reactive pre‐sintering in vacuum combined with hot isostatic pressing (HIP) post‐treatment adding H3BO3 as a sintering additive. The influence of pre‐sintering temperature on the phase composition, microstructure, and PersL performance of (Sr0.97Eu0.01Dy0.02)Al2O4 ceramics was investigated. The results showed that optimum persistent performance was obtained by the ceramics prepared by vacuum pre‐sintered at 1600°C for 3 h and HIP post‐treated at 1400°C for 3 h under 200 MPa in Ar. The persistent initial luminescence intensity exceeded 9200 mcd/m2 after 5 min when the optimum sample was simulated by the daylight irradiation of 1000 lx, and the persistent emission decay time was longer than 14 h. The trap depth was calculated using two methods, and the results showed that the ceramics prepared at pre‐sintering temperature of 1600°C had the highest trap depth. [ABSTRACT FROM AUTHOR]

Utilizing γ‐Al2O3, MgO, and black carbon powders as starting materials, single‐phase magnesium aluminum oxynitride (MgAlON) powders with excellent sinterability were successfully synthesized by carbothermal reduction and nitridation (CRN) method, and the CRN synthesis mechanism was investigated through analyzing phase assemblage and morphology of the powders during heating. As heating to 1700°C, single‐phase MgAlON is obtained, while its O/N ratio can be adjusted by controlling the composition of starting mixture and the CRN process. The MgAlON powders with O/N ratio of 9.52–11.39 (using the mixture with 8.6 wt.% MgO and 5.2 wt.% carbon black, and prepared at 1700°C for 90–150 min or 1720°C for 120 min) exhibit high sinterability. These powders were successfully fast pressureless sintered into ceramics with high transmittance (>80%@3750 nm) at 1880°C for 2.5 h. During the heating process for preparing MgAlON powder, magnesium aluminate spinel (MAS) is first formed at <1500°C, then at 1500–1600°C, along with formation of AlN via CRN and its instantaneous solid solution with MAS, MgAlON is obtained. The phase assemblage and morphology comparison between the Al2O3–MgO–C, Al2O3–MgO, and Al2O3–C powders during heating indicates that carbon and MAS act in concert to inhibit the growth of Al2O3, which contribute to the rapid formation MgAlON and high sinterability of prepared MgAlON powders. [ABSTRACT FROM AUTHOR]

Ceramic pigments are inorganic materials that can be used in industrial applications. Here, we reviewed the works reported in the literature where first-principles calculations based on density functional theory (DFT) have been used to predict the color, electronic, and optical properties, along with experimental confirmation. Recently, theoretically predicting the color of ceramic pigments has been proposed as a new idea, and some studies have been conducted in this field. The research papers calculated the different properties of pigments using DFT and provided a solution to predict the color of ceramic pigments. Herein, it has been shown how methods such as Lanczos, Bethe-Salpeter equation (BSE), and many-body F xc kernel for long-range correction (LRC) model can be used to predict the absorption spectra of ceramic pigments. The absorption spectra data were imported into the Color Viewer software to calculate the color of the pigments. This review presents and discusses recent studies using DFT for ceramic pigments and explains how to complete this theory. [ABSTRACT FROM AUTHOR]

The light waveguiding effect of transparent glass ceramics (GCs) on mechanoluminescence (ML) signals is highly attractive for remote stress sensing and structural health monitoring applications. However, a prerequisite for generating ML in GCs is pre-irradiation with high-energy rays, which not only increases application costs but also poses a risk of GCs devitrification. Herein, we propose a safe, non-destructive, and convenient charging method for the ML of KMgF 3 : Tb3+ GCs, namely ultraviolet (UV) light charging. By effectively filling the intrinsic defects in KMgF 3 : Tb3+ nanocrystal using UV light, we achieved trap-controlled ML in rigid GCs. Moreover, this ML is attributed to thermoluminescence (TL) induced by frictional heating during mechanical stimulation. Additionally, when the GCs powder is combined with flexible polydimethylsiloxane (PDMS), a self-powered (without any pre-charging) ML induced by interfacial triboelectricity can also be achieved, which is similar to the results observed in most flexible ML systems. This work proposes a more straightforward and safer approach for applications such as mechanical sensing based on the ML of transparent GCs. [ABSTRACT FROM AUTHOR]

Y 2 O 3 -MgO composites are promising for mid-infrared windows and domes in harsh environments. However, the insufficient transmittance range (the transmittance >30 % only in ∼2–7 μm) and strong absorption peak (the transmittance <32 % at 7.0 μm) of Y 2 O 3 -MgO composites severely limit their application range because of agglomerations and carbon contamination from organics in the raw materials, currently. In this study, utilizing carbon-free raw materials and high molecular motions, the reduction of carbon contamination and agglomerations within the as-synthesized nanopowers was achieved via the modified co-precipitation synthesis. A highly mid-infrared transparent (the maximum transmittance of 79 % at 6.0 μm) Y 2 O 3 -MgO composite with wide transmittance range (the transmittance >30 % in 2.2–9.7 μm) and weak absorption peaks (the transmittance ≈68.57 % at 7.0 μm) was fabricated by the hot-pressing sintering method using the as-obtained nanopowders in the absence of exogenous dopants. And the modified co-precipitation synthesis is a method with great potential for the development of mid-infrared transparent Y 2 O 3 -MgO composites with wide transmittance range and weak absorption peaks. [ABSTRACT FROM AUTHOR]

Transparent glass-ceramics offer a unique combination of optical clarity and the mechanical strength of ceramics, making them ideal for various advanced applications such as cell phone screens and telescope mirrors. However, traditional fabrication methods involve high temperatures and long processing times, which result in high energy consumption and limitations in material integration. In this study, we explore the fabrication of transparent mullite glass-ceramics from EMT-type zeolites using the spark plasma sintering (SPS) technique to address these challenges. By varying the concentrations of ammonium salts to replace Na+ in the zeolite, we modified the SiO 2 +Al 2 O 3 content and successfully synthesized the mullite glass-ceramics at 950 °C. The resulting glass-ceramics exhibited high transmittance (>65 % in the visible region), improved mechanical properties with a Young's modulus up to 103 GPa, a Vickers hardness of 8.0 GPa, and an indentation fracture toughness of 1.8 MPa m1/2. X-ray diffraction and Raman spectroscopy confirmed the formation of mullite phases, with increased crystallinity and a strengthened glass structure, correlating with higher SiO 2 +Al 2 O 3 content. The study demonstrates the potential of using high Al/Si ratio molecular sieves as precursors for high-performance glass-ceramics, offering significant advancements in both optical and mechanical properties. [ABSTRACT FROM AUTHOR]

Transparent ferroelectric ceramics are popular due to their ability to couple optical and electrical properties. However, simultaneously achieving high electrical and optical performance in ceramics remains a formidable challenge. By using the two-step sintering process combined with a rare earth doping strategy, xLa-24PIN-42PMN-34PT transparent piezoelectric ceramics were prepared, achieving the coexistence of the highest known d33 (>1000 pC/N), excellent transmittance (T = 66.2% at 1600 nm), and the piezoelectric properties decrease by only 26.8% when approaching TC. PFM and in situ XRD results indicate that the parallel stripe-like and watermark-like coexisting ferroelectric domain structures, which are induced by La3+ doping, generate large piezoelectric responses. Light scattering loss is reduced by the small size of the ferroelectric domain structure. Excellent thermal stability is ensured by the tetragonal-dominated morphotropic phase structure. This work provides a valuable idea for the subsequent preparation of transparent ferroelectric ceramics with high performance. [ABSTRACT FROM AUTHOR]

In this paper, Eu3+:(Y0.97Zr0.03)2O3 transparent ceramics with different doping concentrations of Eu3+ were prepared by vacuum sintering. This series of transparent ceramic samples exhibits strong red emission when excited by an electron beam at the keV level. However, color changes observed in the samples after high‐energy electron irradiation. This is due to the capture of electrons by traps related to oxygen vacancies within the Y2O3 lattice. Specifically, under electron beam irradiation, the capture of the electrons by oxygen vacancy‐related defects in the Y2O3 lattice occurs, leading to radiation damage. The color change can be suppressed to some extent by the incorporation of Zr4+ into the Y2O3 lattice, which can effectively suppress the generation of oxygen vacancies. Interestingly, samples with heavy doping of Eu3+ exhibit stronger resistance to electron irradiation damage. Based on the detailed characterizations, including optical transmittance, cathodoluminescence, photoluminescence, thermoluminescence and luminescence decay time, it is found that under heavy doping conditions, Eu3+, which has a stronger cationic character than Y3+ can more effectively suppress the generation of electron traps induced by the oxygen vacancies and the interstitial oxygen in the Y2O3 lattice, thereby enhancing radiation resistance. This research can advance the understanding of defect suppression mechanisms and benefit the application of Y2O3‐based functional transparent ceramics in high‐energy electron and β‐ray irradiation environment. [ABSTRACT FROM AUTHOR]

In this study, Fe2+:ZnSe x S 1-x (0.6 ≤ x ≤ 1) solid solution laser ceramics with cubic crystal structures were prepared for the first time via hot pressing sintering, using FeSe, ZnSe, and ZnS powders. The resulting ceramics exhibit a unique combination of the optical and physical properties of Fe2+:ZnSe and Fe2+:ZnS. An increase in the ZnS content led to a blueshift in the maximum absorption spectra of Fe2+ ions and an enhancement in Vickers hardness. These findings suggest that Fe2+:ZnSe x S 1-x solid solution ceramics could serve as promising gain media for mid-infrared solid-state lasers, offering a novel approach for the development of directly pumped mid-infrared laser systems. [ABSTRACT FROM AUTHOR]

The 8.3 at.% Yb-doped yttrium-scandium-aluminum garnet (YSAG) ceramics were fabricated by a modified reverse co-precipitation method followed by uniaxial and cold isostatic pressing, annealing in air and high-temperature sintering in vacuum. Spectroscopic and lasing properties were investigated in dependence on Y/Sc/Al ratio in ceramic composition. Optical transmission of Yb:YSAG ceramics in visible and near-infrared spectral range exceeds 80 % that indicates a high quality of the Yb:YSAG samples. Among all the ceramics, the Y 2.35 Yb 0.25 Sc 1.00 Al 4.40 O 12 composition demonstrates the best lasing performance and the highest slope efficiency up to 75 %. [ABSTRACT FROM AUTHOR]

Transparent glass with photochromic and luminescent properties has recently garnered considerable interest in optical storage, while the photochromic transparent glass system is still limited. Herein, it is proposed that combining transparent glass matrix with photochromic nanocrystals is an efficient strategy to develop a broader range of photochromic luminescent glass systems. The Yb3+/Tb3+ co‐doped BaMgSiO4 glass ceramics are successfully prepared by a two‐step melt‐quenching approach followed by a thermal treatment in a reducing atmosphere. The glass ceramics exhibit high transparency and distinct coloration, showing a color change between colorless and pink by alternating irradiation between 365 nm ultraviolet light and 473 nm laser. The formation of color centers in the BaMgSiO4 nanoparticles drives the coloration of such glass ceramics. Based on their photochromic and photobleaching behavior, the efficient reversible upconversion luminescence modulation can be implemented with the maximum luminescence modulation rate of 79.83%. The excellent reproducibility and anti‐fatigue of such upconversion luminescence modulation demonstrate the promising application of Yb3+/Tb3+ co‐doped BaMgSiO4 glass ceramics as an optical storage medium. [ABSTRACT FROM AUTHOR]

The commonly used automotive head‐up display (HUD) technology is confronted with the problems of poor stability in organic resin counterpart and the unsatisfactory display effect of projection lighting source. To solve these issues, developing state‐of‐the‐art materials and designing new HUD schemes with a wide color gamut is of necessity. Herein, a series of pure red/green/blue (R/G/B) upconverting (UC) nano‐glass‐ceramics (GCs) containing lanthanide‐doped NaLuF4 nanocrystals (NCs) are synthesized in a cost‐effective, environment‐friendly, and scalable manner, simultaneously achieving high crystallinity (≈45.44%) and high transparency (>80%). Yb3+ is chosen as the sensitizer to Tm3+ (blue UC)/Ho3+ (green UC), due to its large absorption cross section from ground state 2F7/2 to excited state 2F5/2; meanwhile Er3+, Tm3+ co‐doped into NCs can obtain pure red UC emission via promoting the population of Er3+ red‐emitting 4F9/2 state. Consequently, the as‐prepared materials exhibit high R/G/B color purity of > 80% owing to the energy transfer between different lanthanide ions (Yb3+, Tm3+, Ho3+, and Er3+) upon 980 nm near‐infrared (NIR) laser excitation, and possess superior thermal reversibility/water resistivity. Remarkably, two unprecedented HUD prototypes are constructed to demonstrate the application feasibility of developed pure R/G/B UC GCs. [ABSTRACT FROM AUTHOR]

Using the method of non‐reactive sintering of nanocrystalline powders, highly transparent samples of optical ceramics based on solid solutions of yttrium‐scandium aluminum garnets containing 50 at.% scandium in the dodecahedral position and doped with erbium (1 at.%) and ytterbium (0–49 at.%) cations (YSAG:Yb:Er) were produced. The influence of Yb3+ concentration on the crystal lattice parameter, density, refractive index, stability of YSAG:Yb:Er solid solutions during high‐temperature sintering, thermal conductivity, optical transmittance and absorption coefficients in the wavelength range from 200 to 1100 nm, as well as Stokes and anti‐Stokes luminescence, was determined. The revealed patterns make it possible to fine‐tune the physical and chemical characteristics of ceramics for the design of composite laser materials. [ABSTRACT FROM AUTHOR]

Rare-earth-doped transparent ceramics have a broad range of application prospects in high-power lighting, solid-state laser gain media, high-energy radiation detection and imaging, and other fields. With the emergence of new design concepts and application technologies, there is a demand for the preparation of transparent ceramics with novel configurations or composite functions. However, traditional forming methods struggle to achieve the integrated forming of transparent ceramics with special structures and functions. This work focuses on the DLP photocuring 3D printing technology of rare-earth doped transparent ceramics, systematically carrying out the component design of transparent ceramic slurry and the study of printing parameters. By adjusting the ceramic slurry components, YAG:Ce transparent ceramics with a transmittance of about 72% in the visible light range were successfully prepared. Moreover, by using low exposure energy with a smaller curing depth, the warping of ceramic samples was alleviated, achieving the control of the shape of YAG:Ce transparent ceramics. [ABSTRACT FROM AUTHOR]

Through conventional solid-state sintering process, PbNb2O6:Yb3+, Ln3+ (Ln3+=Er3+/Ho3+) ceramics have been fabricated. The structural information of synthesized ceramics was obtained via X-ray diffraction. Scanning electron microscopy was utilized to investigate their morphological properties. The investigation of upconversion photoluminescence properties of the synthesized ceramics was conducted by analyzing upconversion emission spectra upon excitation with 980 nm light. Power dependence studies confirmed the presence of two-photon absorption processes in both PbNb2O6:Yb3+, Er3+ and PbNb2O6:Yb3+, Ho3+ ceramics. Temperature-dependent experiments from 303 K to 513 K demonstrated significant variations in emission intensities and fluorescence intensity ratios (FIR), enabling the assessment of temperature changes. The absolute sensitivity of PbNb2O6 ceramic co-doped with Yb3+, Er3+ ions reached its maximum value of 0.0056 K-1 at 513 K, while the maximum relative sensitivity of 0.697% K-1 was recorded at 339 K. For PbNb2O6 ceramic co-doped with Yb3+, Ho3+ ions, the maximum values of absolute and relative sensitivities were 0.048 K-1 and 0.8% K-1 at 513 K and 473 K, respectively. These results highlight the potential applications of PbNb2O6:Yb3+, Ln3+ (Ln3+=Er3+/Ho3+) ceramics in advanced temperature sensing based on photoluminescence. [ABSTRACT FROM AUTHOR]

For the first time, inductively coupled plasma mass spectrometry (ICP-MS) was developed for determining the target elemental composition of gadolinium–aluminum garnets with the varying composition Gd3–xCexScyAl5–yO12, where x = 0.01–0.16 and y = 0.25–1.75. This fact has a fundamental importance for obtaining optical ceramics with predictable properties. Using the proposed acid mixture and temperature-time program, microwave digestion of these materials and complete transfer of the sample's components into solution were possible. Moreover, we estimated the influence of the matrix composition, sample introduction system and collision cell on the limits of determination (LOD) of impurity elements by ICP-MS (Mg, Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Y, La, Pr, Nd, Sm, Eu, Tb, Er, Ho, Tm, Yb, and Lu). It has been shown that the conditions of mass spectral analysis proposed in this work provide LOD of target analytes in the range of 1∙10−6–4.15∙10−3 wt.%. The accuracy of the obtained results has been confirmed by the added-found method and by analyzing samples with known chemical composition. The standard deviation of repeatability (Sr) of the developed technique lies in the range from 1 to 6%. The developed analysis method is characterized by sensitivity, robustness and multi-elementality. It has application potential for other optical and ceramic materials of similar composition. [ABSTRACT FROM AUTHOR]

In the case of low-temperature fabrication aiming at transparent polycrystalline YAG ceramics with fine grain size, it is easy to retain trace amounts of the intermediate YAP phase, thereby reducing the optical transmittance. To address this issue, adding a small amount of Al 2 O 3 to the starting YAG powder was found to promote the transformation of the residual YAP phase to the YAG phase at low temperatures. The study investigated the effect of sintering temperature and excess Al 2 O 3 amount on preparing transparent YAG ceramics by hot pressing. The transmittance of the Al 2 O 3 -aided single-phase YAG ceramic (2 mm thick) prepared using the two-step sintering reached 43.4 % at 400 nm and 71.8 % at 1064 nm, with a grain size of about 2 μm, while the transmittance of the multiphase YAG ceramic without Al 2 O 3 addition was less than 1 % at both wavelengths. [ABSTRACT FROM AUTHOR]

Highly sinterable nanopowder of 8 mol% yttria-stabilized cubic zirconia (8YSZ) was synthesized via a hydrothermal homogeneous precipitation (HHP) method. The nanopowder with an average particle size of 26 nm, exhibits good dispersibility, narrow particle size distribution and high purity, making it ideal raw material for preparing transparent ceramics. Utilizing spark plasma sintering (SPS) under mild conditions (1200–1350 °C, 80 MPa, 10 min) in contrast to hot isostatic pressing (HIP), cubic zirconia ceramics with favorable optical and mechanical properties were produced. The sample sintered at 1250 °C achieved the highest transmittance of 74 %@850 nm, significantly surpassing the performance of samples prepared from two other commercial 8YSZ powders. Furthermore, the specimen sintered at 1200 °C with a dense fine microstructure (relative density: 99.51 %, grain size: 460 nm), demonstrated the highest hardness and fracture toughness, reaching 15.72 GPa and 1.28 MPa m1/2, respectively. [ABSTRACT FROM AUTHOR]

Er3 +, Na+ co-doped CaF2 transparent ceramics with Er3 + dopant concentration of 3% and Na+ of 0%, 0. 5%, 1.0%, 1.5% and 2.0% were fabricated by the vacuum hot pressing method with 16 mm in diameter and 3 mm in thickness. The average grain size of the obtained Er, Na∶CaF2 powders varied from 28 nm to 36 nm with the shape of sphere. The effects of Na+ doping on the transmittance, microstructure and spectral properties of Er3 + ∶CaF2 transparent ceramics were investigated. The transmittance of all the obtained ceramic samples is above 84% in the wavelength of 1 000 nm. The results show that after introducing Na+ into Er3 + ∶CaF2 transparent ceramics, charge-neutralized Er3 + -Na+ structure formed which prevent Er3 + from clustering. The emission spectra of Er3 + in CaF2 transparent ceramics at around 1. 5 and 2. 7 μm could be modulated by adjusting the concentration of Na+ and the near-infrared fluorescence lifetime at around 1. 5 μm increase with the increasing of Na+ concentration, reaching a maximum of 56.75 ms. [ABSTRACT FROM AUTHOR]

Sesquioxide Lu2 O3 has excellent thermodynamic properties, low phonon energy and strong crystal field characteristics, making it one of the excellent candidates for wideband high-power laser matrix materials in the near-infrared and mid-infrared spectra (1 ~3 μm), and attracting widespread attention in recent years. Since Lu2 O3 has a melting point of up to 2 450 ℃, growing single crystal is extremely difficult, limiting its application development. However, Lu2 O3 belongs to the cubic crystal system and is optically isotropic, making Lu2 O3 -based transparent ceramics a viable option. Compared to single crystal, transparent ceramics can be sintered at lower temperatures (60% ~ 80% of the melting point of crystals) to prepare large-size samples, while the sintering cycle is greatly reduced and more conducive to mass production, so the preparation of Lu2 O3 -based transparent ceramics as a new type of laser material has the potential for a wider range of applications in scientific research, industrial production and daily life. In this paper, the preparation technology and properties of Lu2 O3 -based laser transparent ceramics doped with rare earth ions (Nd3 +, Er3 +, Yb3 +, Tm3 +, Ho3 +) are reviewed. In the future, the development of half-oxide Lu2 O3 -based laser ceramics will be focused on large size, high power output, low scattering characteristics, high thermal stability, and composite structure design to promote the development of highperformance solid-state lasers. [ABSTRACT FROM AUTHOR]