Rare earth gypsum is an industrial by-product generated from the treatment of wastewater produced by the rare earth metallurgical process, and its recycling is a strategic measure for the current green metallurgy and cleaner production. In addition, the filler reinforcing agent for natural rubber in polymers is mainly carbon black or other materials such as calcium carbonate, which will cause a large amount of carbon emissions in the production process. Calcium sulfate whisker (CSW) is a new reinforcing agent in rubber composites, while its surface is hydrophilic and has poor compatibility with organic matrix. This work aims at the above problem by using inorganic trisodium phosphate-organic stearic acid composite modification, thus changing the surface polarity of CSW and improving the compatibility with organic matrix.

20 g/L CSW was dispersed in 100 mL of trisodium phosphate solution (0.005, 0.010, 0.015, 0.020, 0.025 mol/L), then ultrasonicated for 2 min, and stirred at room temperature to make the solution mixed homogeneously. The solution was filtered and washed to obtain inorganic modified CSW (1-CSW). Subsequently, 1-CSW was dispersed in 100 mL of ethanol, and stearic acid (0, 1%, 6%, 11%, 16%, 21% of CSW addition) was added to the solution, and the slurry was heated (60, 70, 80, 90 ℃, and 100 ℃) in an oil bath for a certain time (10, 15, 20, 25 min, and 30 min) under magnetic stirring. The final product was cooled to room temperature, then filtered and washed with anhydrous ethanol for five times, and dried at 100 ℃ for 1 h to obtain the composite modified CSW (2-CSW).

The optimal modification conditions for inorganic-organic surface modification of CSW were determined by one-way experiments: CSW addition as 20 g/L, optimal amount of stearic acid as 6% of CSW, modification time as 10-15 min, modification temperature as 80 ℃, and concentration of trisodium phosphate as 0.02 mol/L. XRD patterns indicated that the modified products were mainly monoclinic hemihydrate (HH) calcium sulfate with the presence of a small amount of monoclinic dihydrate (DH) calcium sulfate, It can be seen that the surface modifier contributed to the transformation of CSW from dihydrate to hemihydrate calcium sulfate. TEM analysis was performed that the surface modifier existed in amorphous form on the surface of the whisker. A transparent coating layer on the surface of 2-CSW can be clearly observed. The enlarged TEM image shows that the average thickness of the hydrophobic layer on the surface of 2-CSW is about 121.26 nm. Infrared spectroscopy analysis shows that inorganic trisodium phosphate and organic stearic acid were successfully modified on the surface of CSW. Thermal stability analysis shows that the first mass loss of CSW is perfectly agreement with the theoretical water content in CSW. The second weight loss is due to the decomposition of stearic acid. XPS analysis of the surface elements and contents proves that trisodium phosphate and stearic acid are successfully encapsulated on the surface of 2-CSW.

The surface modification of CSW was successfully realized through a series of one-factor experiments to change the surface property of this whisker from hydrophilic to hydrophobic. The optimal modification conditions were as follows: concentration of CSW: 20 g/L, stearic acid modifier: 6% of CSW, trisodium phosphate: 0.02 mol/L; modification time: 15 min at 80 ℃. The morphology of CSW remained the original form after the modification, but the crystal structure of the whisker was transformed from DH to HH, and the surface property was changed from hydrophilic to hydrophobic. The contact angle of 2-CSW reached a maximum of 104.23 °, and the thickness of its hydrophobic layer was 121.26 nm. The modification mechanism is that the surface of CSW firstly generates CaHPO₃ and Ca(OH)₂, then undergoes a bonding reaction with stearic acid, generating a nanoscale hydrophobic layer with a C₁₇H₃₅COO-Ca -structured nanoscale. The layer protects CSW from denaturation by the external environment, maintains the unique properties, and confers compatibility with organic substrates.

Previous researches clearly showed the large potential of high-entropy strategy on the adjustment of multiple properties in FEs materials, However, the high configuration entropy only implied the substitution of a high ratio of multiple exotic atoms, and the characteristic of these atoms as well as their influence on the structure of the final compositions were not revealed clearly, even though a large number of high-entropy FEs did not exhibit outstanding performance. Therefore, designing high-entropy FE materials did not involve directly adopting the high-entropy strategy used in traditional structural materials. Instead, it entailed ensuring chemical disorder while utilizing highly adjustable chemical compositions to design functional unit disorder. To achieve functional materials with excellent performance, it is necessary to simultaneously satisfy chemical disorder, structural disorder, and functional unit disorder, it is also the core principle behind designing new high-entropy functional materials. Polarization configuration design is the core for achieving excellent physical properties in FE materials, many special polarization configurations have been reported to show unique electrical properties in many studies. The high-entropy strategy shows strong operability on polarization configuration design because of the unique properties and structure of high-entropy FEs. Furthermore, the high-entropy strategy would also benefit the grain refinement, mechanical property enhancement, and entropy stabilization effects. To elucidate the regulatory mechanism of chemical disorder on polarization disorder, researchers utilized neutron/synchrotron total scattering techniques combined with reverse Monte Carlo methods to achieve atomic-level three-dimensional structure reconstruction. They quantitatively analyzed the intrinsic mechanisms of sub-nanometer ion clusters and the formation of strong polarization fluctuation polarization configurations, it served as a bridge for understanding the relationship between chemical disorder and structural functional unit disorder. Some new technologies, such as machine learning and phase field simulation, could be used for assisting the prediction of high-performance materials among endless high-entropy compositions, and high throughput experiment method can also greatly improve efficiency for exploring new compositions with novel polarization configurations. In the future, further research on high-entropy FEs should focus on the design of more novel polarization configurations to attain better performance of this kinds of materials, thereby to facilitate the application of high-entropy FEs in a wide field.

With the development of society, two-dimensional displays can no longer meet people's needs. Three-dimensional displays can completely reproduce the scene of world, showing the depth of the object, the sense of hierarchy, and reality because the real world is also three-dimensional. At present, there are a lot of techniques to realize three-dimensional displays, including two-dimensional analog three-dimensional displays, binocular parallax stereoscopic displays, and three-dimensional stereoscopic displays. Nevertheless, two-dimensional simulation three-dimensional display does not produce physical depth of field; Binocular parallax stereoscopic display is limited because of the disadvantages of small angle zoom, causing visual fatigue, and needing to assistant equipment. In contrast, three-dimensional stereoscopic display technology has attracted attention due to its realistic display effect, real-time interaction, and multi-angle observation. Among the related technologies, the static volume display technology based on transparent upconversion luminescent materials shows the most significant advantages.

Appropriate composition design is a necessary condition for the nucleation and growth of fluoride nanocrystals in glass. In this study, rare earth doped pure red upconversion luminescent oxyfluoride transparent glass ceramics were obtained via the conventional melt-quenching-thermal annealing method. The glass compositions (in mole) are 60SiO₂-6Al₂O₃-7Na₂CO₃-19NaF-xErF₃-yTmF₃-(8-x-y)YF₃ (x=0-1.6%, y =0-0.4%). The raw materials are SiO₂, Al₂O₃, Na₂CO₃(Sinopharm Chemical Reagents Co., Ltd.), and high-purity NaF, ErF₃, TmF₃, YF₃(Shanghai Macklin Biochemical Technology Co., Ltd), which were weighed, mixed and ground in an agate mortar. The obtained mixtures were then placed in a sealed alumina crucible and melted at 1 550 ℃ for 45 min under ambient atmosphere. Subsequently, the glass melt was poured into a 200 ℃ preheated copper mould and annealed at 400 ℃ for 5 h to relinquish the internal stress. Finally, the obtained bulk glass was heat-treated at 650 ℃ for 2 h to induce in-situ fluoride crystallization inside the glass to obtain oxyfluoride glass ceramics containing NaYF₄ nanocrystals (NaYF₄@glass).

For Er³⁺/Tm³⁺ co-doped NaYF₄@glass, the influence of Er³⁺ doped content was explored and an optimal Er³⁺ concentration of 15% was confirmed. Meanwhile, with the increase of co-doped Tm³⁺ content, the red emission of Er³⁺ gradually enhanced due to the energy transfer process between Er³⁺ and Tm³⁺. Correspondingly, the color purity of red emission increased to realize the pure red emission upon the 980 nm near-infrared laser excitation. In addition, the temperature dependent spectra (from 80 K to 470 K) of 15%Er-2%Tm∶NaYF₄@glass were tested. Owing to the electrons at the ²H_11/2, ⁴S_3/2 and ⁴F_9/2 levels of Er³⁺ were populated independently, there was no direct temperatures-dependent electron correlation between the green (²H_11/2, ⁴S_3/2) and red (⁴F_9/2) levels of Er³⁺ ions. With the increase of temperature, the shape of the emission peak remained basically unvaried, indicating excellent chromatic stability. Ultimately, the Er³⁺/Tm³⁺ co-doped NaYF₄@glass-based three-dimensional prototype display device showed three-dimensional static/dynamic designed red patterns with high color purity and high stability, providing its potential use in new-generation three-dimensional stereoscopic display technology.

In summary, Er³⁺/Tm³⁺ co-doped NaYF₄@glass can be successfully prepared via conventional melt-quenching-thermal annealing method. The optimized 15%Er-2%Tm co-doped NaYF₄@glass can achieve pure red upconversion luminescence due to the energy transfer process between Er³⁺ and Tm³⁺. Owing to that the electrons in the ²H_11/2, ⁴S_3/2 and ⁴F_9/2 levels of Er³⁺ are independently populated, there is not direct temperature-dependent electron correlation between the green energy level (²H_11/2, ⁴S_3/2) and the red energy level (⁴F_9/2) of Er³⁺. Moreover, the Er³⁺/Tm³⁺ co-doped NaYF₄@glass-based three-dimensional prototype display device is constructured. This study can provide a new idea for the development of pure color transparent upconversion materials for three-dimensional stereoscopic display.

The energy transfer between lanthanide ions (Ln³⁺) and transition metal ions (Cr³⁺) typically leads to luminescence attenuation, which hinders their application in temperature measurement. However, this issue can be effectively addressed by synthesizing polyphase glass-ceramics that separate the Ln³⁺ and Cr³⁺ into different nano-crystals.

In this study, we designed polyhedral glass-ceramics (40SiO₂-20Al₂O₃-15LiF-10Ga₂O₃-0.1TmF₃-0.1ErF₃-0.05Cr₂O₃-1YbF₃-0.5SnO) doped with Ln³⁺/Cr³⁺ (Ln³⁺=Er³⁺/Tm³⁺/Yb³⁺). The up-conversion spectra of Tm³⁺ and Er³⁺ in the temperature range of 313-573 K, as well as the temperature-dependent properties of the emission intensity ratio of ²E and ⁴T₂ and fluorescence lifetime decay of Cr³⁺ were systematically investigated. The results demonstrate that Ln³⁺/Cr³⁺-doped polyphase glass-ceramics exhibit excellent performance as a four-mode fluorescence temperature measurement material.

Ln³⁺/Cr³⁺-doped glass samples were prepared using melt quenching technology, where the raw materials were melted in a lifting furnace at 1 500 ℃ for 1 h. The sample was then poured onto a preheated copper plate to 300 ℃ and shaped by pressing it with another copper plate. Subsequently, the sample was annealed in a Muffle furnace at 450 ℃ for 6 h to obtain precursor glass (PG). Finally, the PG sample underwent heat treatment at 780 ℃ for 2 h to produce glass-ceramics (GC780).

X-ray diffraction apparatus was employed to measure the XRD spectra of these samples. FS-5 fluorescence spectrometer was used to measure various spectra including up-conversion and down-conversion spectra at room temperature, power-dependent up-conversion spectra, temperature-dependent up-conversion and down-conversion spectra, as well as temperature-dependent fluorescence lifetime decay curves. Transmission electron microscopy techniques such as selective electron diffraction and high-power transmission electron microscopy were utilized to examine GC780 samples.

The diffraction peaks observed in the XRD pattern of GC780 exhibit excellent agreement with the standard cards of γ-Ga₂O₃ and β-YF₃ respectively, indicating the successful synthesis of polyphase glass-ceramics containing γ-Ga₂O₃ and β-YF₃ grains. The excitation and emission spectra of Cr³⁺ as well as the up-conversion spectra of Er³⁺ and Tm³⁺ indicate no energy transfer between Cr³⁺ and Er³⁺ or Tm³⁺.

In the variable temperature up-conversion emission spectra of GC780 sample within a temperature range of 313 to 573 K, the emission peak intensity ratio (FIR) I₅₂₂/I₅₄₃ and I₆₉₄/I₄₇₄, which change with temperature, were selected for temperature detection. As the temperature increases from 313 K to 573 K, there is a decrease in relative sensitive (S_R) for I₅₂₂/I₅₄₃ with increasing temperature, reaching a maximum value of 1.03%·K^-1 at 313 K. On the other hand, S_R for I₆₉₄/I₄₇₄ initially increases and then decreases with rising temperature, peaking at a maximum value of 1.45%·K^-1 at 473 K. In the down-conversion temperature-changing spectra (303-543 K) of Cr³⁺ excited at 397 nm, the intensity of the luminescence peaks at 615 nm and 720 nm is used to detect the temperature dependence of FIR(I₆₁₅/I₇₂₀). When the temperature is from 303 K to 543 K, S_R gradually decreases with increasing temperature, and the maximum value of 1.74%·K^-1 appears at 303 K. The relative sensitivity is 0.51%·K^-1 at 496 K when Cr³⁺ down-conversion attenuation curve is used to measure temperature dependence.

Polyphase glass-ceramics doped with β-YF₃ and γ-Ga₂O₃ nano-crystals in Ln³⁺/Cr³⁺ (Ln³⁺=Er³⁺/Tm³⁺/Yb³⁺) have been successfully synthesized by melt quenching method in this work. The up-conversion spectra of GC780 were measured in the temperature range of 313-573 K. The maximum relative sensitivities were 1.03%·K^-1 and 1.45%·K^-1, respectively, by selecting I₅₂₂/I₅₄₃ and I₆₉₄/I₄₇₄ intensity ratios. The ²E→⁴A₂ and ⁴T₂→⁴A₂ emission₂ peaks of Cr³⁺ were used for temperature detection, and the maximum relative sensitivity was 1.74%·K^-1 at 303 K. In addition, the Cr³⁺ down-conversion attenuation curve is used to measure the temperature dependence, and the maximum relative sensitivity is 0.51%·K^-1 at 496 K. The Ln³⁺/Cr³⁺ (Ln³⁺=Er³⁺/Tm³⁺/Yb³⁺) co-doped β-YF₃ and γ-Ga₂O₃ nano-crystals polyphase glass-ceramic is thus indicated to be a highly promising competitive four-mode self-calibration temperature measurement material.

Extracted Titanium slag is a type of industrial solid waste produced when titanium is recovered from titanium-containing blast furnace slag using the high-temperature carbonization-low-temperature selective chlorination method. Currently, it can only be disposed of through simple stockpiling and burial, which endangers both the environment and human health. The use of titanium slag to prepare microcrystalline glass with excellent physical and chemical properties is of great significance for the utilization of solid waste resources and the improvement of environmental pollution.

Raw material components and heat treatment systems have a significant impact on the microstructure and mechanical properties of glass ceramics. The current work is based on the chemical composition of titanium slag. high-performance glass-ceramics were prepared by melting sintering method by adding quartz tailings to increase SiO₂ content. Our study examines how the acidity coefficient (M_k) and sintering temperature affect the crystallization, microstructure, physical and chemical properties of microcrystalline glass. Additionally, we reveal the composition of the physical phase of glass ceramics made from titanium slag and the evolution of crystallization. These findings provide a technical foundation for the synergistic treatment of various solid wastes in the preparation of glass ceramics.

Titanium slag and quartz tailings were prepared, combined, ball milled, and sieved accordingly. The required raw materials were weighed exactly, put into a corundum crucible, heated untill the glass liquid melted and clarified. The liquid was then quickly dumped into water, to form glass particles, following a procedure of drying, ball milling, and sieving. The basic glass powder and PVA solution were uniformly mixed before being placed in a press-bar mold and pressed into blank samples, which were then sintered to produce glass ceramics sheet samples.

The chemical composition of the raw materials was evaluated using X-ray fluorescence spectrometry. A thermal analyzer was used to perform the DSC analysis simultaneously. An X-ray diffractometer was used to conduct physical phase analysis on raw materials and glass ceramics samples. The microstructure of the glass ceramics samples was observed using a scanning electron microscope (SEM), and their microscopic composition was analyzed using an energy dispersive-X-ray spectrometer (EDS).

According to the principle of Archimedes, the bulk density and water absorption of each glass-ceramic sample were measured. The bending strength of glass-ceramics was tested by GB/T4741—1999 three-point bending method. JC/T 2097—2011 industrial microcrystalline plate was used to test the acid etching amount of microcrystalline glass.

The morphology investigation reveals that the samples' sintering or fusing steadily improves with an increase in M_k under the same temperature settings. At point of M_k=2.4, the sample begins to soften and distort, whereas at M_k =2.7, it looks to froth.

The XRD spectra of the glass ceramics samples demonstrate that the type and amount of the early crystalline phases vary when the Mand sintering temperature increases. Increasing the heat treatment temperature enhances the intensity of the diffraction peaks of the crystalline phases in low M_k glass ceramics samples. At the same sintering temperature, the content of anorthite in glass ceramics samples rises with increasing M_k, while the content of diopside increases in low M_k and decreases in high M_k.

The surface and cross-section micro-morphology of the glass ceramics samples demonstrates that the sintering temperature is too low and the materials do not attain the sintered state at lower temperature. With the same M_k, the number of holes in the samples decreases with increasing sintering temperature. As the sintering temperature rises, big closed holes become easier to develop.

The features of the glass ceramics samples, together with the results of XRD spectra and SEM analysis, show that Flexural strength and bulk density are mainly related to the type of crystalline phase, crystal content, and appropriately increase the sintering temperature. M_k is conducive to the growth of tremolite and calcium feldspar crystals in the billet, and it also benefits exclusion of porosity, so that the glass ceramics can form a flatter surface, and show higher mechanical-strength, thus to improve the sample's densification, flexural strength, acid resistance, and reduce water absorption as well. At higher acidity coefficients, increasing the SiO₂ content in the base glass causes an increase of the liquid phase, which is beneficial for filling pores, reducing the water absorption capacity of glass ceramics, and improving corrosion resistance under acidic conditions.

With the increase of M_k and sintering temperature, the type and quantity of crystalline phases of glass ceramics samples will undergo high-temperature physical phase reconstruction. Within a certain temperature range, the increase of sintering temperature can promote the growth of crystals in glass ceramics and the intensity of the diffraction peaks of crystalline phases. However, there exists a moderate temperature, above which the transformation of the crystalline phase shows different behavior, that is, low M_k favors the growth of diopside in glass ceramics, while high M_k promotes the formation of anorthite. When the M_k and the sintering temperature are both low, the glass ceramics samples are not completely sintered. This conditions for crystal growth and exclusion of pores are not sufficient. When the M_k and the sintering temperature increase simultaneously, the liquid phase appears in the matrix, which benefits the growth procedure of crystals to form a fixed crystal skeleton. When the sintering temperature is too high or the M_k is too high, the glass matrix begins to melt, and the phenomenon of overcooking occurs, which leads to an increase in the glassy phase and the expansion of pores, resulting in a strong and solid crystal skeleton. The expansion of pores makes the disjointed circular pores in the glass ceramics samples gradually increase. At M_k =1.5 and sintering temperature of 1 190 ℃, the produced material shows a water absorption rate of 0.07%, bulk density of 3.05 g/cm³, acid resistance of 96.6%, flexural strength of 144 MPa, which fully meet the requirements of industrial glass ceramics panels.

CsPbBr₃ perovskite quantum dots have attracted wide attention to be a novel luminescent materials due to their excellent luminescence characteristics. It shows high quantum efficiency (more than 90%) and narrow full width at half-maximum of about 15-20 nm. However, it's sensitive to water, oxygen, and light, due to its inherent ionic properties and low formation energy. The preparation of CsPbBr₃ quantum dot by in-situ crystallization in glass is thus considered to be one of the effective strategies to improve its stability. This work adopts borosilicate as the glass matrix to explore its effect on the glass network structure by changing the molar ratio of CaO/MgO. A further study reveals that there exists regulatory effect on the crystallization behavior and luminescence performance of CsPbBr₃. The potential application of the investigated material in the field of optical filters is also explored.

A series of CsPbBr₃ quantum dot glasses were prepared by the traditional melt quenching-heat treatment method with varying the ratio of CaO/MgO. The obtained glasses were named CAx, where x represents content of CaO. According to the exact ratio, the raw materials are weighed, fully ground in the mortar for 30 min to uniformity. The mixed powder was transferred to a corundum crucible, following with thermal treatment at 1 200 ℃ for 10 min. Subsequently, the melt material was poured into a preheated graphite mold and annealed for 3 h to release the thermal stress until to room temperature. The transparent precursor glass, named PG, was obtained. CsPbBr₃ quantum dot glass was obtained by heat treatment of the precursor glass at different temperatures (450-510 ℃) for 10 h. Finally, the prepared CsPbBr₃ quantum dot glass was cut, polished, or ground into a powder for further characterization and use.

With the increase of the CaO/MgO molar ratio, the average particle size of CsPbBr₃ quantum dots gradually decreases from 19.54 nm to 12.59 nm, indicating that the increase of CaO/MgO molar ratio may change the glass network structure to affect the crystallization behaviours of quantum dots. Due to the different radius scale of Ca²⁺ and Mg²⁺, they have different energies when occupying the sites in glass matrix. When Mg²⁺ is replaced by Ca²⁺, there will be an energy difference, resulting in a decrease in the ability of providing free oxygen, so the BO in the glass increases, which strengthens the glass network. With the increase of the molar ratio of CaO/MgO, the layered structure gradually weakens, and the transition from the layered structure of [BO₃] to the framework structure of [BO₄] leads to the weakening of the layered characteristics and the dense structure of the glass network, resulting in an increase in the crystallization temperature and a decrease in the average size of the quantum dots.

The obtained samples exhibit excellent optical properties. PL spectra of CsPbBr₃ quantum dot glass samples with different CaO/MgO molar ratios were heat-treated at 480 ℃ for 10 h shows strongly varied luminescence intensity. The intensity becomes higher until the peak point with the increase of the molar ratio of CaO/MgO. When CaO replaces MgO in small amounts, the glass network expands because the ionic radius of Ca²⁺ is larger than that of Mg²⁺, and the influence of molecular weight and atomic radius on the glass matrix plays a dominant role, thereby promoting the migration of Cs⁺, Pb²⁺ and Br^-, so that CsPbBr₃ quantum dots are precipitated in the glass matrix and the luminescence is enhanced. When the molar ratio of CaO/MgO is 2∶3 (CA2), the luminescence intensity reaches the maximum value. At this point, the internal quantum efficiency of the CsPbBr₃ quantum dot glass sample is 45.2%, the external quantum efficiency is 36.0% under excitation of 455 nm, and the calculated absorption efficiency is 79.6%. After three times of heating-cooling (298-473 K) cycles, the luminous intensity of the optimal sample gradually returns to the initial value, and the peak emission wavelength and FWHM also show obvious temperature dependence and excellent recovery ability, indicating that the CsPbBr₃ quantum dot glass has good luminescence thermal stability.

CsPbBr₃ perovskite quantum dots were successfully precipitated in borosilicate glass matrix by traditional melt quenching-heat treatment method. Under the same heat treatment conditions, when the molar ratio of CaO/MgO increases, the average size of quantum dots decreases, and the luminescence quantum efficiency increases first and then decreases. The bond breaking effect of Ca²⁺ and the mixed alkaline earth effect make the luminescence performance of the CsPbBr₃ quantum dot glass sample the best when the molar ratio of CaO/MgO is 2∶3, corresponding to an internal quantum efficiency of 45.2%, an external quantum efficiency of 36.0%, and an absorption efficiency of 79.6% under excitation at 455 nm. It also shows good luminescence thermal stability. At the same time, the CsPbBr₃ quantum dot glass crystallization is uniform and exhibits high transmittance, which is promising to be applied in the field of optical filters.

Yttrium aluminum silicate (YAS) glass ceramics, known for their high-temperature resistance, excellent hardness, and mechanical strength, attract wide attention as coating materials for bonding or protecting silicon carbide ceramics. The precipitation of the y-Y₂Si₂O₇ crystalline phase in YAS glass, particularly in comparison with SiC, is advantageous due to the matched coefficients of thermal expansion between y-Y₂Si₂O₇ and SiC. This often leads to its use as a sintering aid or in anti-oxidation coatings for SiC. A glass composition with reported proportions of 22Y₂O₃-19Al₂O₃-59SiO₂ (in mole) has been designed to selectively precipitate only the y-Y₂Si₂O₇ crystalline phase through process engineering, achieving a softening temperature exceeding 1 400 ℃. However, this glass composition initially undergoes a droplet-type phase separation, resulting in the precipitation of y-Y₂Si₂O₇ crystals in regions enriched with Y₂O₃ and SiO₂. The large gap between these two phase-separated regions leads to non-uniform distribution of y-Y₂Si₂O₇ grain sizes. The cross-sectional morphology exhibits a fibrous structure, which may affect the mechanical properties of the glass ceramics. Compared to fibrous structures, spherical grains have a higher stress distribution, providing the glass ceramics with greater strength. Previous studies have shown that TiO₂ and CaF₂ are unsuitable as nucleating agents for achieving uniform and fine grains in YAS glass. In this study, a base glass has a composition of 22Y₂O₃·19Al₂O₃·59SiO_2., The addition of ZnO into the base glass was found to inhibit large-sized phase separation in YAS glass, resulting in a significant refinement of precipitated grain sizes. This led to a substantial improvement in the fracture toughness of the glass ceramics. By observing the crack propagation patterns in the glass ceramics, the toughening mechanism has been elucidated.

On the basis of the glass composition 22Y₂O₃·19Al₂O₃·59SiO₂, a series of glasses with varying compositions, 2xZnO·22Y₂O₃·(19-x)Al₂O₃·59SiO₂ (2x=0, 3, 6, 12, 18, in mole), were obtained by gradually replacing Al₂O₃ with ZnO at a ZnO∶Al₂O₃ ratio of 2∶1. The glasses were subjected to a nucleation temperature (T_g+30 ℃) heat treatment for 3 h, followed by ramping to the crystallization peak temperature (T_c) and holding for 2 h to obtain glass ceramics for testing. Characteristic temperatures of the glasses were determined using DSC at a heating rate of 10 K/min. The glass ceramics, after fine polishing, were etched for 60 s in a 4% HF solution (volume fraction) and then subjected to SEM testing. Vickers hardness of the samples was measured under a 2.94 N load. Fracture toughness (K_Ic) of the samples was determined under the ASTM C-1421-01b standard.

As the amount of ZnO gradually increases, the glass transition temperature (T_g) and T_c of the glass decrease progressively. The addition of ZnO reduces both T_g and T_c of the YAS glasses, which is advantageous for lowering the sealing temperature when used in conjunction with SiC ceramics. XRD patterns, SEM images, and EDS patterns confirm that the mechanism for the precipitation of y-Y₂Si₂O₇ in 22Y₂O₃·19Al₂O₃·59SiO₂ glass belongs to crystallization through phase separation. After the addition of ZnO to YAS glass, nearly spherical grains are precipitated, and the distribution of grains becomes more uniform. With increasing ZnO content, the grain size gradually decreases. The addition of ZnO has a minor impact on the hardness and density of both YAS glass and glass-ceramics. However, a significant improvement is observed in the fracture toughness of the glass ceramics, showing a 65% increase for the glass ceramic containing 18% ZnO compared to the YAS glass ceramic. In glass ceramics formed through phase separation and grain growth, both the size and distribution of grains are uneven. Cracks propagate in a straight-line manner, resulting in longer crack lengths under the same load. In contrast, when cracks propagate in glass ceramics with similar and evenly distributed grain sizes, numerous circumferential cracks around grains occur, leading to increased energy consumption during the crack propagation process and resulting in relatively shorter crack propagation distances.

As ZnO gradually replaces Al₂O₃, both the T_g and T_c of YAS glasses decrease. This leads to reduce the sealing temperature when used as sealing materials. With the addition of ZnO, the crystal phases deposited from the YAS glasses transitions from only the y-Y₂Si₂O₇ grains to two phases, i.e., ZnAl₂O₄ and y-Y₂Si₂O₇. The content of precipitated ZnAl₂O₄ phase increases with the gradual introduction of ZnO. Although no significant increase in hardness was observed following the compositional change from 0 to 18% of ZnO (in mole), a distinct enhancement of about 1 GPa in hardness after crystallization occurs for the glass with ZnO. Despite a decrease in K_Ic of YAS glass from 0.82 MPa·m^0.5 to 0.71 MPa·m^0.5 with the addition of ZnO, the prepared glass ceramics with 18% ZnO (in mole) shows a significant enhancement of K_Ic, reaching a maximum value of 1.92 MPa·m^0.5. The microscopic mechanisms of this enhancement was then revealed by further investigation using SEM.

X-ray detectors could be divided into direct and indirect types, the latter has cheaper and more stable properties. As the key component of indirect detection, scintillators could convert high-energy photons into low-energy ultraviolet or visible photons. However, the preparation process of traditional scintillation single crystals is relatively complex and costly, and the hygroscopicity of materials also puts strict requirements on their working environment and packaging technology. Moreover, the Tl and Cd are toxic and not environmentally friendly. Therefore, it is very necessary to find new scintillators with simple preparation, low-cost, chemically stable, and environmentally stable properties. The glass-ceramics combines the excellent optical properties of nanocrystals with the high stability and transparency of inorganic glass. High-quality and large-area glass-ceramics could also be easily obtained. Rare earth ions have special energy level structures and luminescence characteristics. Under optical excitation, they can absorb energy and emit light of specific wavelengths, thereby enhancing their scintillation performance and luminescence characteristics, and are resistibility to radiation damage. When the scintillation glass is irradiated by external excitation light sources, the rare earth ions absorb the energy and transfer to high energy level state, and then release energy through radiation transitions. In this paper, rare earth ions are doped into glass-ceramics to introduce efficient luminescent centers. The luminescence performance of ZnGa₂O₄∶Tb³⁺ glass-ceramics under X-ray irradiation and its indirect imaging ability are studied.

To prepare ZnGa₂O₄ glass-ceramics composing of 52SiO₂-10Na₂CO₃-22ZnO-16Ga₂O₃-x%Tb₄O₇ (mole fraction), the raw materials were weighed and ground in an agate mortar for 15 min. After uniformly mixing, the powder was transferred to a 30 ml alumina crucible and melted at 1 600 ℃ for 60 min. The sample was poured onto a preheated copper plate at 350 ℃, pressed into shape, and cooling naturally to form the precursor glass. The precursor glass was treated by heating at 600 ℃ for 4 h to release internal stresses. Subsequently, the samples were heat treated at 700, 750, 800, 850, 900 ℃ for 6 h to form glass-ceramics (GC) with different degrees of crystallinity. Finally, these GC samples were polished or ground into powder for further characterization.

The phase of the samples was determined by X-ray diffraction analysis, transmission electron microscopy, and scanning electron microscopy. The photoluminescence properties were analyzed by using the excitation spectrum and photoluminescence spectrum of the Hitachi F-7000 fluorescence spectrophotometer with a 150 W Xe lamp as the excitation source. The transmission spectra were determined by using a TU1810 UV/visible spectrophotometer. A miniaturized X-ray tube with Cu-K_α (λ=0.154 05 nm) radiation source was used for X-ray imaging, maintaining a tube voltage and current of 40 kV and 30 mA, respectively, with a Nikon D500 camera for imaging capture. The radiation luminescence spectra of the samples under X-ray irradiation were measured using a fluorescence spectrophotometer (Ocean Optics, QE Pro).

For the precursor glass treated at the temperature ranging from 700 ℃ to 800 ℃, the samples exhibit a transmittance of over 80% in the wavelength range of 400 nm to 800 nm. However, when the heating temperature exceeds 850 ℃, the transmittance of the samples gradually decreases attributing to the increase of the size of ZnGa₂O₄ nanocrystals precipitated within the glass matrix, resulting in an increase in Rayleigh scattering and the decrease in transparency. Under different doping concentrations of rare earth ion, there is no impurity observed in the XRD diffraction patterns. Additionally, the samples maintain a transmittance of over 80% under different concentrations of Tb³⁺ doping. Based on the intensity of photoluminescence spectra, the optimal Tb³⁺ doping concentration is determined to be 1.5%.

The ZnGa₂O₄∶1.5%Tb³⁺ glass-ceramics exhibits a high absorption coefficient in the range of 0 to 50 keV, with a radiation luminescence yield of 13 000 photons/MeV, which is superior to that of commercial BGO in both absorption coefficient and radiation luminescence yield. Additionally, it exhibits a linear response relationship with X-ray dose rates and demonstrates long-term stability under X-ray irradiation. Indirect X-ray imaging by using this material could clearly visualize the internal structure of printed circuit boards with an imaging resolution of 16 lp/mm. Furthermore, the ZnGa₂O₄∶1.5%Tb³⁺ glass-ceramics could restore its radiation luminescence performance to its initial state via thermal treatment.

ZnGa₂O₄∶1.5%Tb³⁺ glass-ceramics exhibits characteristic emissions of Tb³⁺ under both UV and X-ray irradiation, with a high transmittance of over 80%, which is beneficial for achieving high-resolution X-ray imaging (16 lp/mm). Additionally, under high-energy radiation exposure for a long duration (1 000 h), the RL intensity of ZnGa₂O₄∶1.5%Tb³⁺ glass-ceramics only decreases by 20%, and the radiation damage caused by high-dose X-ray can be restored through simple low-temperature thermal treatment, which reduce the cost of scintillators and meet the long-term lifetime. This study demonstrates that ZnGa₂O₄∶1.5%Tb³⁺ could provide high-quality, efficient, and precise imaging results, and making it promising for applications in medical imaging and non-destructive testing.

With the continuous development of laser technology, ultra-narrow linewidth lasers show important application prospects in many fields. However, the output linewidth of conventional semiconductor laser chips is usually large, which cannot meet the practical application requirements. Therefore, it is of great significance to study the key technologies for preparing ultra-narrow linewidth lasers. As a new type of optical component, volume Bragg grating, with the advantages of tunable diffraction wavelength, stable laser wavelength, and narrow linewidth, has become an effective way to solve this problem. This work tried to prepare 1.5 μm volume Bragg grating (VBG) based on chlorine-containing PTR glass to meet the demand for ultra-narrow linewidth lasers in the fields of new generation of coherent laser communication, LIDAR, and high-precision fiber sensing.

The glass samples were prepared as long strips with a diameter of 5 mm and a length of 28 mm. The thermal expansion was recorded by warming the glass samples from room temperature to 800 ℃ at a rate of 10 ℃/min using a DIL 402PC/4 high-temperature thermal expansion meter from NETZSCH, Germany. The samples of chlorine-containing PTR glass before and after exposure were also tested by differential thermal analysis using a Q600SDT integrated thermal analyser from TA Instruments, USA. This is an important parameter to understand the dimensional stability of the glass during temperature change. A D2 PHASER type X-ray diffractometer from Bruker, Germany was used to analyze the changes in crystal structure of chlorine containing PTR glass before and after exposure, nucleation and precipitation heat treatment to understand the structural evolution and property changes of the material.

A Lambda 750S UV-Vis-NIR spectrophotometer from Perkin Elmer, USA was used to study the optical absorption properties of chlorine-containing PTR glass before and after exposure, nucleation and decrystallisation heat treatments, and to understand its absorption capacity at different wavelengths.

The glass powder was mixed with high purity KBr and pressed into tablets, and then scanned by infrared spectroscopy with a scanning speed of 0.158 cm/s. A Nicolet iS50 Fourier infrared spectrometer from Thermo Fisher Scientific, USA was used. The samples were then analyzed for their infrared transmittance properties. The infrared transmission properties of the samples were analyzed to understand the transmission properties of the materials in the infrared band. An in Via-Peflex type Raman spectrometer from Renishaw, UK was used. The molecular vibration and vibrational information of the samples were further analyzed through Raman spectroscopy to further understand the structure and properties of the materials.

Firstly, the thermal properties of the new PTR glass were investigated. Its transition temperature (T_g) and softening temperature (T_f) were 446.2 ℃ and 499.4 ℃, respectively. These two parameters are important for glass processing and applications. The coefficient of thermal expansion was similar to that of bromine-containing PTR glass in the temperature range of 30-400 ℃, indicating that the substitution of Br^- by Cl^- has a small effect on the thermal expansion properties of PTR glass. Secondly, it was found that NaF nanocrystals were successfully precipitated from chlorine-containing PTR glass after the precipitation heat treatment by XRD (X-ray diffraction) and TEM (transmission electron microscopy) inspection. These nanocrystals were distributed as dark grey elliptical particles with a particle size of 5 nm in the glass. high-resolution transmission electron microscopy (HRTEM) further revealed the lattice structure of these nanocrystals, and the spacing of adjacent crystal planes corresponded to the (111) crystal planes of NaF crystals. In addition, the detection of absorption spectra of chlorine-containing PTR glasses showed a new broad and weak absorption peak at 413 nm, which was attributed to the absorption of plasma AgCl.

Compared with the plasma AgBr absorption peak precipitated in the conventional PTR glass, the plasma AgCl absorption peak of the chlorine-containing PTR glass blueshifted in the UV sepctrum, which supplied the possibility of developing short-wavelength VBG products. In terms of glass structure, Raman and Fourier infrared spectroscopy analyses showed that the structure of chlorine-containing PTR glasses did not change significantly after the precipitation heat treatment. Finally, the article explores the performance of chlorine-containing PTR glasses for VBG applications. The diffraction efficiency of VBG was found to be positively correlated with the refractive index modulation and grating thickness. Under the same conditions of exposure dose and heat treatment process, increasing the thickness of VBG can significantly improve its diffraction efficiency. The experimental results show that the centre wavelengths of VBGs with thicknesses of 10 mm and 16 mm are 1 549.44 nm and 1 549.48 nm, respectively, and the half-height full widths are 0.0611 nm and 0.0570 nm, respectively.

Novel chlorine-containing PTR glass components were designed and prepared using a two-step melting process to produce photothermally sensitive refractive glasses with a homogeneity of 10-6.325 nm UV irradiation led to a decrease in the transition temperature and the onset of precipitation of the PTR glass, and an increase in the precipitation properties, which is very favourable for the preparation of high-quality VBGs. XRD and TEM results confirmed that NaF nanocrystals of an average size of 5 nm were precipitated from the chlorine-containing PTR glass. NaF nanocrystals with an average particle size of 5 nm. Raman and FTIR spectra showed that holographic exposure and heat treatment further enhanced the glass network structure. A reflective volume Bragg grating with a centre wavelength of 1.5 μm was prepared, with a diffraction efficiency of 50% and a half-height full width of 0.0570 nm, which sets the foundation for the development of 1.5 μm ultra-narrow linewidth semiconductor lasers.