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Incorporating magnetic ions into semiconductor nanocrystals has emerged as a prominent research field for manipulating spin-related properties. The magnetic ions within the host semiconductor experience spin-exchange interactions with photogenerated carriers and are often involved in the recombination routes, stimulating special magneto-optical effects. The current account presents a comparative study, emphasizing the impact of engineering nanostructures and selecting magnetic ions in shaping carrier–magnetic ion interactions. Various host materials, including the II–VI group, halide perovskites, and I–III–VI2 in diverse structural configurations such as core/shell quantum dots, seeded nanorods, and nanoplatelets, incorporated with magnetic ions such as Mn2+, Ni2+, and Cu1+/2+ are highlighted. These materials have recently been investigated by us using state-of-the-art steady-state and transient optically detected magnetic resonance (ODMR) spectroscopy to explore individual spin-dynamics between the photogenerated carriers and magnetic ions and their dependence on morphology, location, crystal composition, and type of the magnetic ion. The information extracted from the analyses of the ODMR spectra in those studies exposes fundamental physical parameters, such as g-factors, exchange coupling constants, and hyperfine interactions, together providing insights into the nature of the carrier (electron, hole, dopant), its local surroundings (isotropic/anisotropic), and spin dynamics. The findings illuminate the importance of ODMR spectroscopy in advancing our understanding of the role of magnetic ions in semiconductor nanocrystals and offer valuable knowledge for designing magnetic materials intended for various spin-related technologies. [ABSTRACT FROM AUTHOR]

During devitrification, pre-existing crystallites grow by adding particles to their surface via a process that is either thermally activated (diffusive mode) or happens without kinetic barriers (fast crystal growth mode). It is yet unclear what factors determine the crystal growth mode and how to predict it. With simulations of repulsive hard-sphere-like (Weeks–Chandler–Andersen) glasses, we show for the first time that the same system at the same volume fraction and temperature can devitrify via both modes depending on the preparation protocol of the glass. We prepare two types of glass: conventional glass (CG) via fast quenching and uniform glass (UG) via density homogenization. First, we bring either glass into contact with a crystal (X) and find the inherent structure (CGX/UGX). During energy minimization, the crystal front grows deep into the CG interface, while the growth is minimal for UG. When thermal noise is added, this behavior is reflected in different crystallization dynamics. CGX exhibits a density drop at the crystal growth front, which correlates with enhanced dynamics at the interface and a fast growth mode. This mechanism may explain the faster crystal growth observed below the glass transition experimentally. In contrast, UGX grows via intermittent avalanche-like dynamics localized at the interface, a combination of localized mechanical defects and the exceptional mechanical stability imposed by the UG glass phase. [ABSTRACT FROM AUTHOR]

Due to the rapid advancements in medical radiography, nondestructive inspection, and radiation detection, there is an increasing demand for scintillators that offer both cost-effectiveness and high-resolution X-ray imaging. In this study, we have successfully synthesized transparent glass-ceramic scintillator by embedding Tb3+-doped NaLu 2 F 7 nanocrystals in a glass matrix. This scintillator demonstrates excellent spatial resolution of 20 lp/mm in X-ray imaging due to its high transmittance (over 90% at 550 nm) and intense luminescent intensity when excited by X-ray (151% higher than that of the Bi 4 Ge 3 O 12 scintillator). More significantly, the as-synthesized scintillator exhibits exceptional stabilities at high temperature, moisture levels, and moderate radiation exposure. Notably, any decline in performance caused by long-term exposure to high-dose X-ray can be fully recovered through heat treatment at 350 °C for 30 min. These findings highlight the great potential of NaLu 2 F 7 :Tb3+ glass ceramics as suitable options for high-resolution and retrievable X-ray imaging. [ABSTRACT FROM AUTHOR]

To address the issue of crystal aggregation in CaWO 4 -based glass-ceramics under high temperature or prolonged durations, while also aiming to enhance the luminescent properties, a thermoelectric coupling treatment is introduced during the preparation process of glass-ceramics. In this study, the influence of applying an external DC electric field on the nucleation and crystallization was examined. Techniques such as DSC, XRD, and SEM are utilized to investigate the crystal types and microstructure of the glass-ceramics. Furthermore, the luminescent performance under ultraviolet and X-ray is characterized, with PL, PLE, and XEL spectra being measured. The findings reveal that thermoelectric coupling treatment augments the crystallization content, refines crystal distribution, and enhances luminescent properties. The applied DC electric field provides energy for thermodynamic reactions, reduces activation energy for bond breaking, accelerates ion migration, and facilitates crystal nucleation precipitation. Crucially, it induces polarization of Ti and Zr ions within crystal nuclei, generating electrostatic repulsion between nuclei. These effects mitigate crystal aggregation, refine distribution, and amplify crystal count. This underscores the potential of thermoelectric coupling treatment in synthesizing optical materials utilizing glass-ceramics as luminescent base materials, offering insights for similar researches endeavors. [ABSTRACT FROM AUTHOR]

Glass ceramic dielectric materials with high power density and high energy density have important application value in the miniaturization and integration of lightweight pulse power devices. In this work, SrO 2 –BaO 2 –Nb 2 O 5 –SiO 2 –Al 2 O 3 –B 2 O 3 glass ceramics doped with various contents of CeO 2 were prepared via high-temperature melting combined with temperature-controlled crystallization process. Results showed that CeO 2 doping increased the content of Ba 0.27 Sr 0.75 Nb 2 O 5.78 tungsten bronze phase precipitate from the glass matrix in glass ceramics (from 55.7% to 82.2%), thereby increasing dielectric constant of SrO 2 –BaO 2 –Nb 2 O 5 –SiO 2 –Al 2 O 3 –B 2 O 3 glass ceramics (from 66.5 to 101.9). Besides that, CeO 2 -doped ceramics exhibited excellent temperature stability and low loss (below 0.015). The highest breakdown strength (1590 kV/cm) and energy density (12.88 J/cm3) were achieved in the ceramic with a CeO 2 doping concentration of 3.0 mol.%, being 3.03 times higher than those in undoped glass ceramic. The increase in energy density of the ceramics was attributed to moderate CeO 2 doping concentration that improved the crystallinity (from 83.8% to 89.8%) and reduced the interfacial activation energy of the glass ceramics. [ABSTRACT FROM AUTHOR]

The ZnO–Al 2 O 3 –B 2 O 3 –SiO 2 (ZABS) glass powder was designed and innovatively employed to join AlN ceramics. The crystallization, thermal expansion and wettability behavior of the ZABS glass and glass-ceramic were investigated. The results shows that Zn 3 B 2 O 6 , ZnSiO 4 and Zn 4 B 6 O 13 were precipitated after heat treatments at different temperature, respectively, resulting in a variation in the coefficient of thermal expansion (CTE) of the ZABS glass ceramic. Then guided by the wetting behavior on the AlN ceramic substrate, the joining of the AlN ceramics by ZABS glass at various temperatures and holding times were conducted. Notably, Zn 3 B 2 O 6 was identified to be the primary product in the joints bonded at temperature of 700–800 °C due to the crystallization within the glass and no discernible reaction was observed between the substrate and the interlayer, while ZnSiO 4 was observed at the periphery of Zn 3 B 2 O 6 after 750 °C. Moreover, the crystalline phase Zn 3 B 2 O 6 gradually grew with the temperature and holding time increasing as the glassy phase gradually diminished, resulting in a reduction of the strength and reliability of the joints. The optimal flexural strength of the joints was 156 ± 11 MPa at 700 °C for 30min. The reason for the high strength can be attributed to the interactions between the glass precipitated crystalline phase interlocking each other and the glass phase tightly bonded with the crystalline phase. [ABSTRACT FROM AUTHOR]

β-CaSiO 3 with a low dielectric constant and low dielectric loss is one of the decisive components of commercial calcium borosilicate (CBS) low-temperature co-fired ceramic substrate. However, achieving a high degree of crystallization of β-CaSiO 3 is difficult in CBS glass ceramics because of the competitive multiphase crystallization during sintering. We have shown that six-coordinated magnesium can be used to weaken the silicate network to achieve a high degree of crystallization of β-CaSiO 3 in CBS glass ceramics. The appropriate MgO content to ensure a large amount of MgO 6 production gradually destroys the [SiO 4 ] tetrahedral network as the temperature increases, resulting in a β-CaSiO 3 content of 76.2 vol%, when the MgO content is 2.71 mol%. The resulting material has the lowest dielectric constant (4.95@15 GHz) and dielectric loss (8 × 10−4@15 GHz), and the best three-point bend strength (77.43 MPa). Our work provides an effective method of changing the crystallization by modifying the glass network in silicate-based glass ceramics with a low dielectric constant. [ABSTRACT FROM AUTHOR]

Lithium-zinc-germanate glass-ceramics doped with Mn ions are synthesized by volume crystallization method. Structural studies show nucleation of different forms of lithium germanate crystals depending on the isothermal treatment regime of the initial glass. With the increase of the heat treatment temperature and the lithium content in the initial glass, the [GeO 4 ] /[GeO 6 ] ratio in the nucleated crystalline phases increases. The initial distribution of Mn2+/Mn3+/Mn4+ is defined by the Li 2 O/ZnO ratio in the glass composition: the ratio growth increases the contribution of Mn4+ over the Mn2+ and Mn3+. Low-temperature heat treatment of initial glass leads to uprise of intense red emission of Mn4+ ions in the octahedral environment. High-temperature heat treatment leads to occurrence of intense green emission related to Mn2+ ions in a tetrahedral environment. Discussions on all transformations of symmetry, the crystal field strength of Mn ions' environment and their valence state based on the results of optical spectroscopy, ESR and XRF studies are provided. The maximum quantum yield of red luminescence is 61%, and of green luminescence is 23%. The synthesized glass-ceramics can be used as a luminescent converter of the UV LED radiation with the maximum energy efficiency of 20%. [Display omitted] [ABSTRACT FROM AUTHOR]

0.75(0.4Na 2 O-0.1K 2 O-0.5Nb 2 O 5)-0.25(0.87SiO 2 -0.13BaO) glass-ceramics were prepared by a traditional melting method to optimize the crystallization kinetics. We obtained a glass network with high degree of polymerization (DOP) by crystallization at different temperatures and achieved a high energy storage density. The increase of crystallization temperature has promoted the precipitation of ferroelectric phases Na 0.9 K 0.1 NbO 3 and NaNbO 3 with high dielectric constant (1200–2000), promoted the increases of grain size from 0.76 μm to 1.33 μm, and reduced the gap width from 3.71eV to 3.22eV. When the crystallization temperature increased to 1000°C–1100 °C, Ba 2 NaNb 5 O 15 with low dielectric constant (∼460) increases, grain boundaries appear, and dielectric constant and BDS decrease. Among all the samples, the sample crystallized at 900 °C showed homogeneous and dense microstructure (grain size∼0.91 μm). The experimental data confirmed that the glass sample crystallized at 900 °C achieves low dielectric loss (<0.005) and high dielectric constant (∼122). The glass sample crystallized at 900 °C sample had a maximum energy storage density of 3.65 J/cm3, a power density of about 54 MW/cm3 and a super-fast discharge speed of 38 ns at 660 kV/cm. [ABSTRACT FROM AUTHOR]

Oxy-fluoride glass-ceramics (GC) has advantages such as low phonon energy of fluorides and the excellent physical and chemical properties of oxides. Here we report the synthesis of a series of transparent oxy-fluoride GCs with various doping contents of Er3+ (0.2 mol%-10 mol%) synthesized under different temperatures, and their UCL properties under the excitation of 1550 nm laser. We found that Er3+-doped glass matrix with NaYF 4 fluoride nanocrystals demonstrated greatly enhanced UCL compared with as-prepared glass. The samples showed red light emission with 3 mol% Er3+ as the optimal doping content. The wavelength of UCL could be fine-tuned by the temperature of heat treatment, and 893 K seems to be the optimal temperature. We also studied the photoelectric conversion characteristics of the optimal Er3+ doped oxy-fluoride GCs with a polycrystalline silicon solar cell under the excitation of a 1550 nm laser as a possible strategy to effectively improve the photo-electric conversion efficiency of solar cells. [ABSTRACT FROM AUTHOR]

Mullite-based fibers are promising candidates for reinforcement fibers for ceramic matrix composites. This paper summarizes the high-temperature properties of continuously produced mullite and zirconia-toughened mullite (ZTM) fibers. Special attention was devoted to the continuous sintering of fibers with complete mullite crystallization while avoiding grain growth. The fibers were annealed between 1000 and 1500 °C for 25 h in air and analyzed at room temperature. The addition of ZrO 2 did not significantly reduce the average matrix grain size. With increasing annealing temperature, notable changes in the phase composition occurred. Pristine fibers contained mullite and intermediary γ-Al 2 O 3 and an amorphous phase, leading to an ongoing mullite crystallization up to 1200 °C. Grain growth and changes in the phase composition led to a decrease in Weibull strength. ZTM fibers showed a lower relative strength retention than mullite fibers, but contained up to 76 % (1310 MPa) of their initial strength at 1300 °C. [ABSTRACT FROM AUTHOR]

During the blast furnace (BF) smelting process, the viscosity of BF slag affects greatly the quality of molten iron, slag-iron separation, gas flow distribution, etc. After discharged from BF, the crystallization of molten slag at low cooling rate will decrease the glass content and hydration activity of slag, which occurs more easily in the tempting heat recover system of molten slag for energy saving and emission reduction. The glassy slag at quite cooling rate is the valuable resource to replace virgin raw material to conserve the natural resource for producing the value-added materials, which facilitates the circular economy and sustainable development. This paper firstly describes the generation of BF slag, and discusses the research methods of viscosity-structure of the slag and detailed effects of basic oxides, acidic oxides and amphoteric oxides. Then, the characterization methods for crystallization of slag, determination of critical cooling rate, precipitated phases and the effect of chemical components are summarized. With regard to the preparation of glass-ceramics from BF slag, the effects of heat treatment, nucleation agent, addition amount of the slag and main chemical components are expounded. At last, the future challenges and attentions on the viscosity, crystallization and glass-ceramics preparation of BF slag are scrutinized. [ABSTRACT FROM AUTHOR]

Dy 2 O 3 –Sm 2 O 3 co-doped transparent glass ceramics (GCs) containing NaBi(WO 4) 2 crystalline phase were prepared by melt-curing-crystallization method. The optimal heat treatment condition is 580 °C/2 h. The optimum incorporation concentration of Dy 2 O 3 is 0.4%, exceeding which a quenching phenomenon dominated by quadrupole-quadrupole interactions emerges. Meanwhile, when the concentration of Dy 2 O 3 was fixed, the chromaticity coordinate of the sample moved the cool white light region to the warm white light region as the concentration of Sm 2 O 3 increased. The temperature-dependent emission spectra of the 0.4% Dy 2 O 3 -0.7% Sm 2 O 3 co-doped GC samples show that emission intensity at 575 nm at 185 °C still reaches 80% of the room temperature. The thermal quenching activation energy was 0.1537 eV and the activation energy after the addition of Mo6+ was 0.1957 eV. This study indicates that Dy 2 O 3 –Sm 2 O 3 co-doped GCs containing NaBi(WO 4) 2 crystalline phase can achieve light-color tunable emission, which is potentially valuable for solid-state color rendering and illumination applications. [ABSTRACT FROM AUTHOR]

In this work, glass samples were obtained by melt-quenching in the binary system (100-x)KPO 3 -xNb 2 O 5 with x = 20, 30, 40, and 50 mol%. Thermal properties investigated by DSC together with structural investigations by Raman spectroscopy allowed to understand the structural effect of Nb 2 O 5 incorporation in the potassium phosphate glass network. A transparent glass-ceramic has also been produced by heat treatment of the 50KPO 3 –50Nb 2 O 5 glass sample. Density, molar volume, atomic packing, and refractive index were determined and increased with Nb 2 O 5 content. Chemical resistance in several corrosive aqueous solutions was found to increase with Nb 2 O 5 content and crystallization. Vickers hardness as well as elastic modulus and hardness obtained from nanoindentation experiments also strongly increased with higher niobium contents, indicating that not only optical properties but also chemical and mechanical properties are improved with niobium incorporation in the phosphate glass network. [ABSTRACT FROM AUTHOR]

Photochromic luminescent glass-ceramics attract lots of attention as an optical storage medium owing to their large storage capacity, reversible luminescence modulation, simple operation, etc. Herein, a kind of phosphosilicate glass containing AgBr nanoparticles was designed and prepared, which can realize the color reversible transformation between light yellowish-green and brown by alternating 365 nm light illumination and thermal treatment at 300 °C. The mechanism of photochromism and bleaching of the glass is related to the generation and decomposition of Ag0 clusters. Relying on the re-absorption effect, the emission intensity of Eu3+ ions could be reversibly regulated, showing the maximum luminescence contrast of 74 %. A good fatigue resistance and reproducibility of transmittance and luminescence modulation could be observed in cycle measurements, demonstrating its potential in the optical memory field. [ABSTRACT FROM AUTHOR]

In recent years, researchers have prepared glass-ceramics using a mixture of multiple solid waste materials, which is an effective and resourceful way to use and store solid waste. However, solid waste usually contains multiple heavy metals, which presents challenges during the mixing and co-solidification processes. In this study, high-performance glass-ceramics with low leaching were prepared from blast furnace slag (BFS). The synergistic curing mechanism of BFS glass-ceramics for heavy metals Cr, Mn, Cu, Zn, Ni, and Co was investigated in detail, as well as the migration pattern and storage state of heavy metals under different heat treatment stages and different Cr contents. The results show that the increases in temperature and Cr 2 O 3 content contribute to the incorporation of heavy metals into the crystal lattice and promote crystal growth. Excessive crystallization of spinel causes aggregation, which further curtails the leaching of heavy metals. The leaching concentration of heavy metals mainly depends on the heavy metal content in the glass network and the degree of network polymerization. Thus, spinel acts as a crystal core for the solidification of heavy metals, while augite and glass phases act as a double barrier to physically encapsulate them, which is effective for the storage of a wide range of heavy metals. Furthermore, the physical and chemical properties of BFS glass-ceramics are consistent with the Chinese industry standard "Glass-ceramics plate for industrial application" (JC/T 2097-2011). This study provides important theoretical support for the synergistic solidification of multiple heavy metals in glass-ceramics, as well as insights into the preparation of glass-ceramics by mixing BFS with other solid wastes. [Display omitted] [ABSTRACT FROM AUTHOR]

Reaching high densification upon sintering β-tricalcium phosphate (β-TCP) has always been challenging. Its combination with bioactive glass (BG) is a common strategy to increase its densification, but still highly limited due to phase transformation. Cold sintering process (CSP) has gained attention in the search for alternatives to traditional sintering (TS), but the number of bioceramics explored is still limited. Thus, the main goal of this work was to use S53P4 BG as a sintering agent of β-TCP in CSP. Pellets of β-TCP/S53P4 (0, 30, and 60 wt%) were consolidated by CSP at 200 °C while being pressed at 166 MPa and compared with pellets sintered by TS at 1200 °C. Whereas β-TCP pellets showed no densification by CSP, the addition of 30 and 60 wt% S53P4 led to a significative increase in their density, of 76 ± 4% and 85 ± 3%, equivalent to the pellets consolidated by TS. CSP pellets were consolidated without showing the crystallization of S53P4 and presented a highly densified microstructure. Both CSP and TS pellets showed apatite formation in simulated body fluid (SBF) after 7 and 14 days. Thus, CSP has shown to be a promising alternative to TS when consolidating β-TCP/S53P4. [Display omitted] • Nearly fully densified β-tricalcium phosphate (β-TCP) and bioactive glass S53P4 composites were consolidated by cold sintering process (CSP). • The densification of the pellets showed to be proportional to the content of bioactive glass in the composite, both on CSP and upon sintering at 1200 °C. • While the composites sintered at 1200 °C showed crystallization in rhenanite and sodium calcium silicate, the X-ray diffractogram of the CSP pellets corresponded only to β-TCP. • Pellets consolidated by CSP showed similar behavior in simulated body fluid when compared to pellets consolidated at 1200 °C. [ABSTRACT FROM AUTHOR]

Quantitative composition‐structure‐property (C–S–P) relationship analysis is a promising approach to correlate structural features with properties of glasses that have complex structures and lack long‐range order. In this study, the structure and spectroscopic properties of two typical P2O5‐MO‐K2O‐Al2O3 (M = Mg, Ba) quaternary phosphate laser glasses doped with Nd3+ ions are calculated and predicted. By using the nearest‐neighboring congruently melting compounds in the phase diagram as "component and structural motifs", correlations with properties and insights on glass behaviors can be obtained. Two key physical properties and five spectroscopic properties are predicted and verified with an error of less than 5% and 10%, respectively. Furthermore, two C–S–P databases with more than 1000 glass compositions are established for designing and optimizing new laser glasses. The results show that this approach not only gets rid of the traditional qualitative research method which relies on empirical formulas, but also promotes the quantitative calculation and predictable design of glass research. [ABSTRACT FROM AUTHOR]

We report the effects of sodium phosphate dodecahydrate (Na3PO4·12H2O) as a foam stabilizer on the crystalline phases, microstructure, and properties of foamed glass–ceramics derived from solid industrial wastes. Our findings reveal that Na3PO4·12H2O acts as a pore structure stabilizer, enhancing pore uniformity by releasing P2O5 during decomposition. Additionally, it lowers the softening temperature and viscosity by supplying Na2O. X‐ray diffraction analysis demonstrates that Na3PO4·12H2O does not alter the primary crystal types but does influence the crystallinity and morphology. With an increase in Na3PO4·12H2O content, the porosity and water absorption improve, but the bulk density, thermal conductivity, and compressive strength decrease. The optimal properties are achieved with 4 wt% Na3PO4·12H2O, resulting in significantly higher compressive strength compared to foamed glass–ceramics prepared from other solid wastes. This study provides valuable guidelines for effectively reusing solid industrial wastes to fabricate foamed glass–ceramics. [ABSTRACT FROM AUTHOR]

In this work, alumina foam ceramics (AFC) were prepared by foaming method, and AFC/salt composite phase change materials were prepared by melt infiltration method using AFC as skeleton materials. The results showed that AFC had good chemical compatibility with Na 2 SO 4 and NaCl. The salt contents of AFC/Na 2 SO 4 and AFC/NaCl were 37.8 wt% and 31.7 wt%, respectively, with compressive strength of 100.1 MPa and 72.8 MPa, thermal conductivity of 5.53 W/m·K and 6.40 W/m·K, and energy density of 1129 J/g and 1019 J/g, respectively. Due to the better wettability, AFC and Na 2 SO 4 form a chimeric structure, which has better binding and bonding strength, and is not prone to molten salt leakage. AFC/ Na 2 SO 4 is expected to be applied to industrial waste heat recovery and solar thermal power generation with periodic temperature changes. [ABSTRACT FROM AUTHOR]

Here we report a novel quadrilayer structure glass/ceramic with multicolor emission, which has a great potential to be used as a light converter for laser lighting with low blue light and high color rendering index. The multilayer glass/ceramic was prepared by controlling the crystallization of the double-layer Sr 1.07 Eu 0.03 Al 2.2 Si 1.8 O 8 /Sr 1.09 Sm 0.01 Al 2.2 Si 1.8 O 8 glass. The outer layers of the glass/ceramic are the ceramic layers and the inner layers are the glass layers. Hexagonal Sr 1.1 Al 2.2 Si 1.8 O 8 is the only crystal phase precipitated during the crystallization process and these crystals are highly oriented in growth. The Ra and CRI values of the white light-emitting LD prepared by employing the multi-layer glass/ceramic as the light converter and a 405 nm LD as the pump source are both more than 90. This work provides a novel and enlightening idea for the design and preparation of the multilayer glass/ceramic with multicolor emission. [ABSTRACT FROM AUTHOR]

The phase‐field model for the description of the solidification processes with the glass‐crystal competition is suggested. The model combines the first‐order phase transition model in the phase‐field formalism and gauge‐field theory of glass transition. We present a self‐consistent system of stochastic motion equations for unconserved order parameters describing the crystal‐like short‐range ordering and vitrification. It is shown that the model qualitatively describes the glass‐crystal competition during quenching with finite cooling speed. The nucleation of the crystalline phase at slow cooling speeds and low undercoolings proceeds by a fluctuation mechanism. The model demonstrates the tendency to amorphization with the increase of its cooling rate. [ABSTRACT FROM AUTHOR]

In this study, the photoluminescence (PL) behavior of two aluminosilicate glass series containing alkali-niobates ranging from 0.4 to 20 mol% was investigated. The glasses exhibit an intense visible emission centered at ~18,400 cm−1 for the peralkaline series and at higher energies (~19,300 cm−1) for the metaluminous glasses. However, the photoluminescence emission intensity varies significantly with the niobate content and the bulk chemistry. PL and fluorescence lifetime measurements indicate that the broad emission bands result from the overlap of different niobate populations, whose distribution changes with niobate content. The distinct PL behavior in the two glass series was related to the structural evolution of the niobate units upon niobium addition. An enhancement of the visible emission was observed for a higher fraction of distorted [NbO6] units. Eu-doping was carried out as a structural probe of the glass network, and also to determine if these glasses could be used as potential rare earth element (REE) activators. The crystal field strength around Eu ions is strongly dependent on the bulk chemistry and the niobate content. Furthermore, the peralkaline series showed energy transfer from the host [NbO6] to Eu3+, confirming the feasibility of exploring niobate glasses and glass-ceramics as lanthanide ion-activated luminescent materials. In addition, glass-ceramics (GCs) containing alkali-niobate phases with a perovskite-like structure were developed and studied to verify the optical performance of these materials. It was verified that the bulk chemistry influences crystallization behavior, and also the photoluminescence response. The transparent GC from the metaluminous series exhibits a quenching of the Eu3+ emission, whereas an enhanced emission intensity is observed for the peralkaline GC. The latter shows a strong excitation-dependent PL emission, suggesting energy transfer and migration of electronic excitation from one Eu population to another. Additionally, Eu3+ emissions arising from the D 1 5 and D 2 5 excited states were observed, highlighting the low phonon energy achievable in niobo-aluminosilicate hosts. [ABSTRACT FROM AUTHOR]

Cutting force is one of the most important physical quantities in the cutting process. Cutting force directly determines the generation of cutting heat and affects tool wear and machined surface quality. In this work, based on the geometric analysis of the turning tool, the cutting edge was discretized, and the local parameters of each cutting edge were calculated. According to the formation and assumption of brittle material chips, considering the energy dissipation in the process of chip formation, the cutting force of each cutting edge element was calculated. Then, the theoretical model of three-dimensional turning force of glass–ceramics was established by adding the forces contributed by all cutting edge elements. The change of tool geometry angle can lead to the change of local cutting parameters at each point on the cutting edge, thereby affecting the variation of cutting force. In order to evaluate the cutting force model, the turning experiment of fluormica glass–ceramics was carried out, and the influence of tool geometry angles (normal rake angle γn, tool nose radius rε, and tool cutting edge angle κr) on the cutting force was discussed. The predicted results are in good agreement with the measured results. This model can provide theoretical guidance for the efficient turning strategy of glass–ceramics. [ABSTRACT FROM AUTHOR]

The recovery of spent hydrogenation catalysts occupies advantages in both alleviating environmental burden and resource shortage. Whereas, the development of conventional hydrometallurgical recovery of molybdenum (Mo) and nickel (Ni) from spent MoNi/Al 2 O 3 catalysts has been limited by the numerous processes and the accompanying generation of waste liquids and residues. Herein, A new recycling route for the preparation of spent hydrogenation catalysts with low thermal expansion coefficients (CTE) was proposed, which has the advantages of short process, green environment and high value utilization. The Li 2 O–Al 2 O 3 –SiO 2 –B 2 O 3 (LASB) parent glass containing Mo and Ni were obtained by melting with different contents of the spent catalysts. The thermal expansion coefficient of the glass was minimized to 6.08 × 10−6/°C at an addition of 25 wt% of the spent catalysts. Moreover, according to the crystallization peak in DTA curve, glass-ceramics were prepared by one-step crystallization heat treatment at different crystallization temperatures. The main crystalline phase of the glass-ceramic precipitated by heating at 685 °C is β-quartz (Li 2 Al 2 Si 3 O 10), which gives the glass-ceramics the lowest coefficient of thermal expansion (0.96 × 10−6/°C) of glass-ceramic as well as the maximum density (2.45 g/cm3) and Vickers hardness (705.8 Hv). Furthermore, the activation energy (354.65 ± 17.42) kJ/mol) and Avrami index (5.39) associated with crystallization were extracted from the fitting of different theoretical model, indicating the three-dimensional crystallization of the LASB glass-ceramics. This technology provides a waste-to-material strategy for hazardous waste and a clean production route for the preparation of the functional glass-ceramics. [ABSTRACT FROM AUTHOR]

In this study, oxyfluoride glasses with chemical composition of 45SiO 2 –15Al 2 O 3 –10BaO–30BaF 2 -xTbF 3 (x = 0.2, 0.4 and 0.6 (mole ratios)) were prepared through the conventional melt-quenching method. Raman and FTIR spectra as well as molar volume calculations proved the creation of more non-bridging oxygens (NBOs) in presence of more TbF 3 content. Accordingly, absorption edge in UV–Vis spectra showed a slight red-shift to longer wavelengths. The glass with 0.4 mol ratios of TbF 3 , exhibited the highest photoluminescence emission and its green-to-blue intensity ratio was 0.66. Therefore, this sample was chosen and heat treated at 630, 650 and 675 °C to prepare glass ceramic samples. For the sample heat treated at 650 °C, photoluminescence intensity increased and green-to-blue intensity ratio reached 0.69. Also, lifetimes of green and blue emissions increased from 3.35 ms to 3.67 ms and from 2.95 ms to 3.10 ms, respectively, when the base glass heat treated at 650 °C. Formation of BaF 2 nanocrystals in glass ceramics moved the UV–Vis absorption edge to longer wavelengths significantly. Increment of the weak and dangling bonds in crystallized samples reduced Fermi energy, indirect and direct optical band gap energies from 3.792 eV to 3.301 eV, from 3.522 eV to 3.093 eV and from 4.095 eV to 3.582 eV respectively, which led to higher semiconducting behaviors. [ABSTRACT FROM AUTHOR]

Solid waste-based lightweight glass ceramics aroused a great deal of attention with the introduction of green building materials. This material demonstrated high performance while alleviating the pressure of waste accumulation. Lightweight glass ceramic was fabricated from phosphorus tailings and coal gangue as raw materials in this work. The effects of phosphorus tailing ratios (50 wt.% - 100 wt.%) and heat-treatment temperatures (1130 °C – 1170 °C) on the pore morphology, properties and toxicity evaluation of lightweight glass ceramics were investigated. Differential Scanning Calorimetry (DSC), and Thermogravimetric mass spectrometry (TG-MS) tests were performed to characterize the sintering behavior of lightweight glass ceramics. The research found that Fe 2 O 3 in the phosphorus tailings and C and FeS 2 within the coal gangue achieve in-situ foaming by creating the gas at elevated temperatures. Results revealed that increasing the proportion of phosphorus tailings facilitated the generation of the molten glassy phase, which favored the formation of bubbles and the expansion of pores. The average pore size of lightweight glass ceramics enlarged from 15.33 μm to 75.02 μm upon increasing the amount of phosphorus tailings from 50 wt.% to 100 wt.%. Increasing the amount of the glassy phase could be achieved by adjusting the heat-treatment temperature. This not only formed a protective film preventing water penetration into the interior of the lightweight glass ceramics but also effectively protected them from corrosion by acidic and alkaline solutions. The water absorption dropped dramatically from 16.44 % to 3.63 % and the corrosion resistance was greater than 98 % when the temperature rose from 1130 °C to 1170 °C. From the toxicity evaluation, the leaching toxicity of Cr, Cu, Pb and Zn in lightweight glass ceramics was 4 orders of magnitude below the limiting value and an extremely low potential ecological risk index (RI = 3.32) was obtained. The optimal preparation parameters were phosphorus tailings addition of 80 wt.% and a heat-treatment temperature of 1160 °C. The corresponding porosity, bulk density, compressive strength, water absorption, acid resistance and alkali resistance were 51.29 %, 1.38 g/cm3, 10.62 MPa, 4.81 %, 98.63 % and 99.96 %. The findings of the research offered a feasible solution for the development of novel green building materials, simultaneously reducing the environmental hazards of solid wastes. [ABSTRACT FROM AUTHOR]

Glass ceramic capacitors with ultra-fast discharge speed and high energy density play a key role in pulse power systems. However, the low dielectric performance of glass ceramics limits their energy storage density. To reinforce the dielectric properties and energy storage capacity of glass ceramics, the microstructures and contents of the ceramic phases composing BaO–Na 2 O–Nb 2 O 5 –SiO 2 –TiO 2 –ZrO 2 glass ceramics can be effectively controlled by adjusting different crystallization conditions. At the optimum crystallization temperature of 950 °C, the maximal theoretical energy storage density of BaO–Na 2 O–Nb 2 O 5 –SiO 2 –TiO 2 –ZrO 2 dielectric glass ceramics reaches 9.54 J/cm3 at 1394 kV/cm, which is 1.47 times that of dielectric glass ceramics crystallized at 750 °C. Moreover, glass ceramics exhibit a rapid discharge rate of approximately 0.237 μs and superior power density (2.39 MW/cm3) at 800 kV/cm. Significant enhancement in energy storage performance of the above ceramics is attributed to the component regulation and the reduction of interface polarization. [ABSTRACT FROM AUTHOR]

In this study, Gd 2 O 3 –Ga 2 O 3 -GeO 2 -Nd 2 O 3 glasses and glass ceramics were synthesized, and their structural, thermal, and crystallization characteristics were analyzed. Our findings indicate that substituting Gd 2 O 3 for Ga 2 O 3 positively influences the enhancement of bridge oxygen content and network structure stability. Heat treatments at different temperatures showed no significant impact on the crystal phase type but did alter the crystallization rate. Optimal conditions were identified: a Gd 2 O 3 /Ga 2 O 3 ratio of 0.6 facilitated the production of transparent glass ceramics containing a single-phase GdGaGe 2 O 7 nano-crystal. Notably, the glass ceramic nucleated at 780 °C for 24 h and crystallized at 840 °C for 5 min exhibited superior performance. Despite a 6% reduction in transmission rate, the emission intensity at 1060 nm increased by 1.5 times. This material holds promise for various applications in solid-state lasers operating within the 1.06 μm region. [ABSTRACT FROM AUTHOR]

The microscopic properties of fluoride grains are known to play critical roles in the up-conversion luminescence properties of phosphors carrying rare-earth-based luminescence centers. To study the effect of different heating methods during preparation on the microstructure and up-conversion luminescence performance of oxy-fluoride glass-ceramics, we synthesized Er3+/Yb3+ co-doped NaYF 4 nanocrystals containing transparent glass-ceramics by microwave heat-treatment and the normally heating methods. We characterized the internal structure of glass-ceramics by X-ray diffraction, transmission electron microscopy, mid-infrared spectroscopy, and Raman spectroscopy. While glass-ceramics samples prepared by both methods have extremely high optical transmittance similar to that of a glass, the microwave heat-treatment promoted faster grain growth rate, the glass-ceramics sample had better crystallinity and much improved up-conversion luminescence intensity compared to the sample obtained by the normally heating method. [ABSTRACT FROM AUTHOR]

The effects of Al3+ and crystallization heat treatment on the luminescence and radioluminescence properties of CsPbBr 3 perovskite quantum dot borophosphate glass-ceramics were investigated using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), and Raman spectroscopy. Al3+ can suppress the free migration of ions in glass and control the formation of Pb–Br by improving the stability of the glass. Spectral analysis results revealed that small quantum dots are beneficial for achieving high-efficiency photoluminescence, whereas large microcrystals are beneficial for achieving high-efficiency radioluminescence. The experiment also proved that excessive Br− is not conducive to the precipitation of CsPbBr 3 perovskite in glass and thus deteriorates the photoluminescence and radioluminescence properties of the glass. [ABSTRACT FROM AUTHOR]

In this work, the CuCl/KNO 3 and AgCl/KNO 3 mixed molten salts were selected to prepare chemically strengthened Cu containing glasses and Ag–Cu containing glasses at 460–500 °C used two-step ion-exchange method. The effects of treatment temperature on ions concentration distribution, transmittance, strengthening effect, chemical stability and ion release of samples were studied, the antimicrobial activity of samples was evaluated. The results demonstrated that K+ ions, Ag+ ions and Cu+ ions were successfully introduced onto the surface of the glass. Cu and Ag existed mainly in the form of monovalent ions, but the metal Cu or metal Ag formed when the temperature was high, making the glass appear pink or yellow, respectively. The surface compressive stress of Cu containing glasses was 508–602 MPa, and that of Ag–Cu containing glasses was 587–672 MPa, both of which showed stress relaxation at temperatures above 480 °C. The samples' Vickers hardness rose by 4–16 %, the density and chemical stability were also improved. Ion-exchanged glass was capable of releasing Cu+ ions or Ag+ ions steadily in an aqueous environment, which had a significant inhibitory effect on the growth of staphylococcus aureus with favorable antimicrobial effect. Compared with the original glass, the ion-exchanged glass prepared in our work was not only incorporated two antibacterial active ions (Ag+ ions, Cu+ ions), but also has improved mechanical properties and chemical stability. [ABSTRACT FROM AUTHOR]

Among all the cathode materials in lithium-ion batteries (LIBs), V 2 O 5 has gained a lot of attention due to its high theoretical specific capacity (∼440 mAh g−1). However, only some of the lithium-ions can be reversibly extracted after inserting into V 2 O 5 cells, making the actual reversible capacity of the crystalline V 2 O 5 cathode material much lower than its theoretical specific capacity. In this work, we prepared Li 2 O–V 2 O 5 –P 2 O 5 ternary glass by melt-quenching method. Subsequently, we grew nano-sized crystals and super-lattice structures in the glass matrix by precise heat treatment. Systematic structural, electrochemical tests and first-principles computations have shown that a reasonable amount of super-lattice structure can significantly enhance the electronic and ionic conductivity of glass matrix materials. Benefiting from this, the LVP-70-2 composite cathode exhibited excellent lithium storage performance with a stable reversible capacity of nearly ∼280 mAh g−1 at 50 mA g−1 and an outstanding cycling performance of a remaining capacity of 90 mAh g−1 at 1600 mA g−1 after 200 cycles. [ABSTRACT FROM AUTHOR]

By combining the spectroscopic quality of a crystalline phase with the outstanding thermal and chemical stability of the matrix glass, nanocrystal‐in‐glass composites (NGCs) exhibit excellent optical properties. However, strong interfacial diffusion occurs during high‐temperature encapsulation, leading to the erosion of the nanocrystals and detrimental effects on the final performance. The control of interfacial diffusion has so far relied on intuition and experience, with the underlying physical mechanisms remaining largely unknown. In this study, through atomistic simulations and experimental verification, we have developed atomic models of NGCs, revealing the dynamic characteristics of the interface and elucidating how the glass structure can regulate the interface diffusion. Finally, we demonstrate how a tunable interface can be achieved through compositional adjustments of the glass matrix. [ABSTRACT FROM AUTHOR]

Lithium silicate-based glass ceramics have evolved as a paramount restorative material in restorative and prosthetic dentistry, exhibiting outstanding esthetic and mechanical performance. Along with subtractive machining techniques, this material class has conquered the market and satisfied the patients' needs for a long-lasting, excellent, and metal-free alternative for single tooth replacements and even smaller bridgework. Despite the popularity, not much is known about the material chemistry, microstructure and terminal behaviour. This article combines a set of own experimental data with extensive review of data from literature and other resources. Starting at manufacturer claims on unique selling propositions, properties, and microstructural features, the aim is to validate those claims, based on glass science. Deep knowledge is mandatory for understanding the microstructure evolution during the glass ceramic process. Fundamental glass characteristics have been addressed, leading to formation of time-temperature-transformation (TTT) diagrams, which are the basis for kinetic description of the glass ceramic process. Nucleation and crystallization kinetics are outlined in this contribution as well as analytical methods to describe the crystalline fraction and composition qualitatively and quantitatively. In relation to microstructure, the mechanical performance of lithium silicate-based glass ceramics has been investigated with focus on fracture strength versus fracture toughness as relevant clinical predictors. Fracture toughness has been found to be a stronger link to initially outlined manufacturer claims, and to more precisely match ISO recommendations for clinical indications. [ABSTRACT FROM AUTHOR]

The reutilization of granite sludge generated in granite cutting and processing possesses economic and ecological benefits. In this study, high‐strength glazed glass‐ceramics were prepared entirely from granite powder using dense sintering and instantaneous glaze firing. The densification and glaze formation are clarified in terms of phase evolution to study their effects on the flexural strength and surface glossiness of the glass‐ceramics. The milling process promotes particle refinement and the removal of colored minerals, thus increasing the powder whiteness and sinterability. After dense sintering at 1100°C, instantaneous glaze firing at high temperatures decreases the flexural strength while greatly increases the surface glossiness of the glass‐ceramics due to the dissolution of quartz and feldspars in the liquid phase. After the acid‐leached powder was densely sintered and fired with a rapid heating of 50°C/min to 1300°C, the pinhole‐free glazed glass‐ceramic has a flexural strength of 112.5 MPa and a surface glossiness of 54.7 GU (glossiness unit), meeting the quality requirements of the bright glazed tiles in the market. The stepwise sintering process provides a simple processing route for recycling granite sludge into decorative construction tiles and high‐temperature glazes, promising the scalable and value‐added utilization of granite sludge. [ABSTRACT FROM AUTHOR]

Geopolymer ceramics undergo a series of thermal phase transitions, progressing from an amorphous geopolymer gel to a crystalline phase, and eventually to an amorphous glass phase as the temperature increases. However, there is a lack of mechanism understanding regarding to the crystallization process and the subsequent thermal degradation. Here, we fundamentally investigated the kinetics of nepheline formation in Na‐based geopolymer systems and its thermal stability up to 1400°C. Nepheline crystallization is controlled by bulk nucleation and three‐dimensional crystal growth based on the Avrami factor of 4.64, where the activation energy of nepheline formation is 350.59 kJ/mol. High thermal stability of geopolymer ceramics is achieved due to the appearance of nepheline up to 1400°C with the Si/Al ratio ranging from 1.40 to 1.94, while melting and amorphous structure are formed above a higher Si/Al ratio of 2.22. The nature of sintering for geopolymer ceramics consists of shrinkage, expansion and shrinkage corresponding to dehydroxylation, crystallization, and densification, leading to a thermal shrinkage of 21% at 1400°C. [ABSTRACT FROM AUTHOR]

Exploring the influence of sintering atmosphere on the formation of ZrSiO4 is of great significance. Herein, ZrSiO4 ceramics were prepared by the solid‐state reactive sintering method under different atmospheres (air, N2, vacuum, and Ar + 5%H2). The influence of sintering atmosphere on the phase and microstructure evolutions of the obtained ceramics was investigated. It was found that ZrSiO4 ceramics could be prepared under air atmosphere, whereas ZrO2–SiO2 glass ceramics were obtained under N2, vacuum, and Ar + 5%H2 atmosphere, which may be due to the fact that the oxygen‐deficient environment inhibits the transformation of ZrO2 to tetragonal phase (t‐ZrO2) and the crystallization of amorphous SiO2. The results demonstrated that t‐ZrO2 and c‐SiO2 were beneficial for the formation of ZrSiO4. The ZrSiO4 conversion fraction was up to 96.16% under air atmosphere at 1450°C for 6 h. Furthermore, the predominant formation mechanism of ZrSiO4 was the reaction between t‐ZrO2 and c‐SiO2. [ABSTRACT FROM AUTHOR]

Mechanical properties of porcelain based on feldspar porcelain as a matrix with SiC particles as a reinforcing phase were studied in terms of the effects of SiC content, firing temperature, and holding time. A maximum flexural strength of 122 ± 4 MPa was achieved for a sample with 8 wt% SiC content treated at 1260°C for 30 min, which is 90.6% as high as than that of the unmodified matrix (64 ± 5 MPa). The fracture toughness and elastic modulus of the former sample were 1.71 MPa · m1/2 and 89.975 GPa, respectively. Because the thermal expansion coefficient of SiC (4.40 × 10−6/°C) is smaller than that of the glass phase (6.60 × 10−6/°C), the SiC particles remain in a state of compressive stress after the porcelain cooling. This characteristic restricts crack growth and offsets the tensile stress of the glass phase, restraining crystal growth owing to the tensile stress pinning the grains, such that the mechanical properties are improved. [ABSTRACT FROM AUTHOR]

Leucite glass–ceramics are excellent dental restorative materials, but they have relatively poor fracture toughness and high hardness, which leads to lower damage tolerance and counter‐tooth wear, respectively. These materials are also susceptible to bacterial infections and biofilm formations. Here, we report a versatile material leucite–silver‐based glass–ceramic to address the aforementioned shortcomings. Silver was incorporated in leucite (K2O·Al2O3·4SiO2) glass–ceramic to improve the fracture toughness, reduce hardness, and impart antibacterial characteristics. Silver (2, 5, 10, and 15 wt.%) was added into the leucite glass matrix by two approaches, that is, using silver nanoflakes (AgNFs) and using precursor (AgNO3), via thermal decomposition, followed by a sintering process. The incorporation of silver was confirmed by X‐ray diffraction, transmission electron microscopy, and energy‐dispersive spectroscopy. Results showed that the hardness of the leucite‐silver composite material was reduced by 30% and indentation toughness improved by 47% as determined by Vickers indentation. Antibacterial characteristics of the material were investigated against Staphylococcus aureus and Escherichia coli bacteria. Scanning electron microscopy was done to see the morphology of damaged bacteria and colonies. Further, antibacterial activity was quantified using the colony formation unit counting method. All the samples showed antibacterial activity and the sample with the highest silver content, that is, 15 wt.% showed maximum potential to damage the bacteria. Inductively coupled plasma‐atomic emission spectroscopy analysis is done in phosphate buffer saline solution to quantify the amount of silver leached out from the leucite‐silver glass–ceramic samples. It was seen that the cumulative leached‐out silver over 3 days was less than 4 μg/cm2 which is well within the daily tolerance limit (5 μg/kg/day) of silver for the human body. Further, to confirm the cell viability, a cytocompatibility test is performed using L929 fibroblast and AW8507 oral cell lines. Cell viability of more than 80% was achieved, suggesting their suitability for biomedical applications. It is believed that the developed material can be a potential candidate for various applications like dental restorations, implants, and coating material for different substrates (SS 304, SS 316, Ti6Al4V, etc.) to protect them from bacterial infections and biofilm formation, etc. [ABSTRACT FROM AUTHOR]

Alkali-aluminosilicate glass and glass-ceramics can be effectively strengthened by ion-exchange if compression is introduced into the surface, which have been widely used in many electronic devices, especially for mobile phones. In this work, the transparent lithium aluminosilicate glass-ceramics with eucryptite crystalline phase were ion-exchanged in the mixed x NaNO 3 + (100－ x) KNO 3 (wt %, x = 60, 70, 80, 90, 100) molten salts at 420 °C for 4 h. With the increase of NaNO 3 concentration in the molten salts from 60 to 100 wt %, the depth of stress layer increase from 98 to 104 μm, and the surface compressive stress increase to the maximum ∼500 MPa at x = 80 and then decrease. In addition, there is also a K+-rich layer observed with the depth of ∼25 μm. The ion-exchange takes place in both crystalline and residual glassy phases, and thus leads to the microstructural modifications, including the amorphization of eucryptite and the presence of lithium phosphate. Upon ion-exchange, the Vickers hardness of glass-ceramics increase from 7.03 GPa to the maximum ∼7.62 GPa (x = 80), and the bending strength from 198 MPa to the maximum ∼510 MPa (x = 90). The improvement in mechanical properties is mainly related to the generation of surface compressive stress layer. Meanwhile, the amorphization and transformation of crystalline phase during the ion-exchange process are probably conductive for the reduction of surface cracks and defects, leading to the enhancement of mechanical properties, especially for the bending strength. [ABSTRACT FROM AUTHOR]

Effect of micro-crystallization (based on annealing time and temperature) on near-infrared (NIR)-shielding properties of Li 0.09 K 0.23 WO 3 doped glass was investigated. The tungsten bronze doped glass was prepared by a facile melt-quenching technique. Structure and optical properties of the glass and glass-ceramics were characterized by X-ray diffraction analysis (XRD), Raman, and UV–Vis–NIR spectrophotometry, respectively. Increasing the annealing temperature increases in the range from 400 °C to 500 °C, the tungsten-functional unit Li 0.09 K 0.23 WO 3 structure, which is responsible for NIR-shielding, changes the structural state from amorphous state to crystalline state gradually. Thus, the NIR-shielding properties of glass are significantly enhanced. Furthermore, annealing glass samples at 450 °C, during timeframe from 2 h to 8 h, causes crystallization and grain growth of the functional units, thus NIR-shielding property of the glasses is enhancing. It worth to be mentioned, that the increase of annealing temperature and time duration causes excessive grain growth in the glass matrix, which leads to decreasing of the optical transmittance in the visible light wavelength region. We have found, that the glass sample annealing temperature is at 450 °C with treatment time of 6 h yields the best results. In such manner the optical transmittance at λ = 1500 nm wavelength is 16.5 % and the highest transmittance of visible light wavelength region reaches 65 %. We conclude, that the NIR-shielding properties are adjustable and can be tailored by annealing temperature and time duration, which is expected to enhance the design and vary visual aspects of energy-saving windows. [ABSTRACT FROM AUTHOR]

The nanocrystalline 0.35SiO 2 -0.65ZrO 2 (65 mol% monoclinic ZrO 2) glass-ceramic was successfully fabricated via a high-pressure cold sintering process (CSP), displaying remarkable nano hardness and elastic modulus of 12.5 and 154.8 GPa, respectively. We conducted a thorough investigation of the influence of NaOH solution concentration, liquid-to-solid mass ratio, sintering temperature, and pressure on the phase compositions, microstructural evolution, and densification. Notably, excessive NaOH concentration (>0.7 M) results in the transformation of SiO 2 from an amorphous phase to α-quartz, hindering densification. However, below 0.7 M, increasing NaOH concentration enhances the densification processes. Furthermore, higher temperature and pressure contribute to improved densification. It is worth mentioning that there is no grain growth for the ZrO 2 phases during the CSP, indicating that the densification of the nanocrystalline 0.35SiO 2 -0.65ZrO 2 glass-ceramic is primarily governed by the glass phase. [ABSTRACT FROM AUTHOR]

Zirconolite (CaZrTi 2 O 7) glass-ceramic is considered as a potential stable matrix for the immobilization of Pu or minor actinides (Np, Am, Cm). In this work, the phase combination and evolution of glass (SiO 2 –Al 2 O 3 –Na 2 O–CaO–ZrO 2 –TiO 2 –B 2 O 3) with La as an actinide surrogate were investigated during the process of heating and cooling. By employing controlled cooling process, the zirconolite glass-ceramic with a controllable crystal size was successfully fabricated in borosilicate glass. The results demonstrate that heating and cooling exhibit distinct phase combinations. Both crystallization temperature and duration exert a significant influence on the composition of crystalline phases and microstructure. During the cooling of the melt, an increased degree of supercooling leads to an enhanced crystallization of zirconolite and a significant reduction in crystal size. The experimental results demonstrate that the optimal condition for preparing zirconolite glass-ceramic is held at 950 °C, for 4 h by one-step method, at which time the crystal exhibits a slender acicular morphology with a size of about 30 μm. Most of the simulated nuclides are enriched in crystals, and the rest are dissolved in glass. Zirconolite exhibits thermodynamic instability at elevated temperatures (1000 °C–1100 °C). Following the phase transformation, a proportion of Zr sequestered by titanite, while any excess Zr is either remain dissolved in the glass or gets precipitated as baddeleyite. For La, Al and other elements previously fixed in zirconolite, they are re-released to the glass and partially fixed by titanite, which may be detrimental to the long-term release behavior of the waste forms. In the aqueous durability test, both zirconolite glass-ceramic and phase transformation samples exhibited a low leaching rate, with LR Si , LR Zr , and LR La values of approximately 5 × 10−3, 4 × 10−6, and 6 × 10−6 g·m−2·d−1, respectively, after 28 days of leaching. By controlling the cooling process (one-step method), this paper provides useful information on the preparation of zirconolite glass-ceramic. [ABSTRACT FROM AUTHOR]

The sintered glass-ceramic always has an uneven microstructure due to the surface crystallization, which limits the enhancement of its mechanical properties. In the present work, Cr 2 O 3 was added into CaO–MgO–Al 2 O 3 –SiO 2 –CaCl 2 glass as the nucleating agent, and the low-pressure (14 kPa) sintering technology was utilized to promote the densification process of the glass frits (0.42–2 mm). It was found that by adding 1 wt% of Cr 2 O 3 , the bulk crystallization can be achieved inside the glass particle and the microstructure of the glass-ceramic became more homogeneous. Correspondingly, the bending strength was improved from 127 to 147 MPa, and the Vickers hardness was enhanced from 6.5 to 6.7 GPa, comparing with the Cr 2 O 3 -free glass-ceramic. The current study confirmed the positive impact of nucleating agent in the performance of sintered glass-ceramic, which also provided a route for the utilizations of CaCl 2 -and Cr 2 O 3 -bearing wastes. [ABSTRACT FROM AUTHOR]

The effects of three additives, CaF 2 , TiO 2 and P 2 O 5 , on the crystallization, microstructure and properties of glass-ceramic glazes in the CaO–Al 2 O 3 –SiO 2 –ZrO 2 system were investigated in detail. The results showed that CaF 2 reduced the viscosity of the glaze and promoted the crystallization of t-ZrO 2 , as well as its conversion to ZrSiO 4. The addition of TiO 2 and P 2 O 5 produced a phase-separated structure that favored t-ZrO 2 crystallization but inhibited its transformation into ZrSiO 4. The stronger the phase separation, the more pronounced this inhibition was. In glass-ceramic glaze containing P 2 O 5 (named PG), t-ZrO 2 was present even at 1250 °C, about 100 °C higher than in conventional zirconium glazes. Further TEM-EDS mapping analysis revealed that Zr was preferentially dissolved in the P-rich droplets. The lack of SiO 2 and the diffusion barrier at the phase-separated interface were the main reasons for suppressing the transition from ZrO 2 to ZrSiO 4. After firing at 1200 °C, PG had a coexistence of ZrO 2 and ZrSiO 4 and exhibited optimal performance, with an L* value of 93.31, a whiteness of 86.5, a gloss of 91.9°, a hardness of 7.06 GPa and a roughness of 30.2 nm. These findings are valuable for the controlled crystallization of Zr-based glass ceramics and related products. [ABSTRACT FROM AUTHOR]

Diopside-Like based ceramics as the main crystalline phase (expressed as 'Diopside') were prepared via one-step sintering using extracted titanium slag (ETS) and coal fly ash (CFA) as raw materials. The effects of CFA content and sintering temperature on the crystal phase composition, microstructure, properties and crystallization kinetics were studied by X-ray fluorescence, X-ray diffraction, scanning electron microscopy, and inductively coupled plasma emission spectrometry. According to the findings, the addition of CFA supplemented the deficiency of Si and Al in ETS and balanced the Ca/Al/Si molar ratio in the system. Moreover, at the CFA doping of 20 %, melilite was gradually transformed into 'diopside' at 800–1100 °C that further remained stable at 1160–1200 °C. 'Despite' the fact that the crystallization activation energy increased and the Avrami index was at its lowest level (1.75), the crystallization temperature was reduced, whereas the crystallization rate increased, causing the ceramic body and surface to crystallize and thereby improving the properties of ceramics. Sintering at 1180 °C for 1 h resulted in ceramics with 'diopside' as the primary crystal phase composition. The water absorption, linear shrinkage, bulk density, bending strength, and acid resistance were respectively 1.3 %, 13 %, 2.89 g cm−3, 141.8 MPa, and 97.36 %. Finally, 'diopside' possessed the higher acid resistance than melilite and anorthite. [ABSTRACT FROM AUTHOR]

The continuous development of portable devices and new energy vehicles has led to an increasing demand for high‐performance lithium‐ion batteries (LIBs), and anode materials, as a key part of LIBs, are being explored. Germanium‐based anode materials are considered to have good potential for application because of their high theoretical capacity. In this work, a germanium phosphate glass precipitating GeO2 microcrystal was designed and used in LIBs as anode materials for the study. The presence of GeO2 crystals increases the specific surface area and also provides more reaction sites for lithiation reaction, resulting in the capacity of the glass anode. The discharge specific capacity of the germanium‐phosphorus glass anode was as high as 740.9 mAh g−1 after 600 cycles at a current density of 500 mA g−1. Interestingly, the synergistic effect between the glass matrix and the crystals not only increases the cycling capacity but also enhances the cycling stability of the structure. [ABSTRACT FROM AUTHOR]

The Al 2 O 3 /ZrO 2 (Y 2 O 3) eutectics were prepared by the melt-grown and seeding melt-grown methods, two non-directional solidification methods. We identify the three-dimensional morphology and crystallographic orientations of the Al 2 O 3 /ZrO 2 (Y 2 O 3) eutectics using the focused ion beam milling with electron backscattered diffraction and the transmission electron microscopy. The results show that in the colony, there are three parts of the ZrO 2 (Y 2 O 3) phase composed of interconnected three-level rods. The crystallographic orientation of the colony axis is variable, but the growth directions of the rods show a commonality, < 2 ̅ 0 2 1 > A , in the Al 2 O 3 / ZrO 2 (Y 2 O 3) eutectics, which has been also clarified by the interface structure analysis. The analysis of the preferred growth orientation not only enlightens the growth mechanism of Al 2 O 3 /ZrO 2 (Y 2 O 3) eutectics but also provides a method for the design of novel eutectics. [ABSTRACT FROM AUTHOR]

This study aims to investigate the phase transformation, thermal behavior, microstructure evaluation and surface feature of the barium aluminosilicate (BAS) glass-ceramic glaze by changing barium oxide (BaO) and aluminium oxide (Al 2 O 3) amounts. Differential thermal analysis (DTA) analysis showed that the first crystallization occurred at 800 °C and referred to the celsian formation, and crystallization temperature increased as Al 2 O 3 content increased. Characteristic temperature and high thermal viscosity behavior was examined by hot-stage microscope analysis and the Vogel–Fulcher–Tammann (VFT) equation. X-ray diffraction (XRD) analysis showed that replacing Al 2 O 3 with BaO resulted in an enhanced celsian (Ba 0.8 Al 1.6 Si 2.4 O 8) phase. On the other hand, increasing Al 2 O 3 content promoted the corundum (α-Al 2 O 3) phase. The glassy and crystalline phase amount was determined by using Rietveld method. Field Emission Scanning Electron Microscope (FESEM) observations showed rectangular, strip-like celsian crystals, unshaped corundum crystals and porous microstructure. Surface roughness and the height distribution of surfaces were supported by 3D topographic mapping and determined according to ISO 4287. The highest BaO-contained R1 exhibits lower peaks with 190 µm and valleys with 80 µm, on the contrary, the highest Al 2 O 3 -contained R5 has high peaks with 252.7 µm, and deep valleys with 150 µm. Finer celsian crystals and lowest surface roughness ensured the cleanability of the surface and resulted in Class 5 according to ISO 10545-14. When Al 2 O 3 content increased by 30 wt% and above, cleanability began to weaken, resulting in Class 1 and Class 2. The surface has become opaque with an increase in the Al 2 O 3 content. [ABSTRACT FROM AUTHOR]