Search

In this work, phospho-silicate glasses with SiO2–P2O5–Na2O–F-MO (M = Ca, Sr, Zn) composition were prepared by using the conventional melt quenching technology. Structural, physical, and chemical property tests were used to analyze the effects of different SrO and ZnO content on the structure and properties of the glasses. The results showed that the glass stability varied nonlinearly as CaO was replaced by SrO, which was mainly related to the different positions of Sr2+ and Ca2+ ions breaking the network connection in the network structure, and the substitution of ZnO for CaO led to a continuous decrease in the stability of the glasses. The immersion experiment showed that SrO doping was more feasible than ZnO doping to improve the biological activity of the glasses, and the doping of ZnO promoted the dissolution of ions in the glasses. The obtained results indicated that the glass samples prepared in this paper have potential biological activity, which has potential applications in dental treatment.

In this work, CuO-doped MgO-Al2O3-SiO2 based glasses have been synthesized successfully through conventional melt quenching method, and the effect of CuO content on the structure and properties of the glasses was investigated. The results revealed that CuO could act as a glass modifier to depolymerize the silicate network and its effect was superior to that of MgO. In addition, the main crystalline phase was α-cordierite (Mg2Al4Si5O18), indicating that copper ions did not participate in the formation of the crystalline phase, and still existed in the interstitial position. The characteristic absorption band around 750 nm owing to the 2B1g→2B2g transition of Cu2+ ions appeared on the optical transmittance spectra, which confirmed the existence of Cu2+ ions in the tetragonally distorted octahedral sites. The luminescence center was caused by Cu+ ions, and the luminescence lifetime decreased with the addition of CuO. The dielectric constant and dielectric loss increased with the increase of CuO content, indicating an increase in the insulation performance. Finally, the obtained chromaticity coordinate parameters indicate that the prepared CuO-doped magnesium aluminosilicate-based glasses can be applied in optical and electrical fields.

The effects of adding ZrO2 and TiO2 at the expense of MgF2 on the crystallization, microstructure, mechanical properties, thermal properties and electrical properties of mica glass-ceramics based on the SiO2–MgO–MgF2–K2O system were investigated by the differential scanning calorimetry (DSC), X-ray powder diffraction (XRD), scanning electron microscopy (SEM), microhardness tester and resistivity tester. The electrical properties were discussed emphatically. The results showed that the additions of ZrO2 and/or TiO2 at the expense of MgF2 effectively increase the viscosity, the glass transition temperatures (Tg) and the crystallization temperatures (Tp) of the glasses. The crystallization activation energy (Ec) of the amorphous glasses varied with the nucleating agents was discussed in depth. It was discovered that the nucleating agents had no effect on the crystal phase type but had a certain effect on the crystallinity and microstructure. Tetrasilicic fluoromica and enstatite were precipitated at different crystallization temperatures. Due to the non-stoichiometric ratio of tetrasilicic fluoromica crystal, the prepared glass-ceramics had high dielectric constant (24.4–34.3) and volume resistivity (>2 × 1011 Ω cm) at 25 °C, and the dielectric loss was almost zero.

Preparation of glass ceramic foam materials from solid waste is a practicable technique that could alleviate the environmental challenges caused by solid waste and obtain products with high added value. We prepared glass ceramic foams with high porosity and high strength using electrical insulators waste and red mud as raw materials. The effect of different electrical insulators waste/red mud ratios on the pore structure, physical properties, mechanical strength, and chemical stability of the glass ceramic foams was investigated. In addition, a leaching test of heavy metal ions and multiple recycling of the prepared glass ceramic foams were analyzed. The results showed that with increasing electrical insulators waste content, the different chemical components of the waste promoted the formation of a liquid phase, the composition of which transformed from a Ca-Al-Si-O to an Al-Si-O glass system, and therefore, caused a variation in the pore structure of the glass ceramic foams. Meanwhile, the bulk density, porosity, compressive strength and acid corrosion resistance of the prepared glass ceramic foams displayed a satisfactory trend. The leaching toxicity results of the prepared glass ceramic foams revealed that the heavy metal ions were solidified by the formed glass phase during sintering. When the electrical insulators waste/red mud ratio was 8/2, the glass ceramic foams exhibited optimal comprehensive properties in the prepared samples, with a bulk density of 0.66 g/cm3, porosity of 73.6% and compressive strength of 11.3 MPa.

Na-Fe-Al-P-O-N glasses have been successfully prepared by melting batches at 1050–1150 °C under N2 atmosphere. The amorphous nature of the Na-Fe-Al-P-O-N glasses was verified by an X-ray diffractometer. The structural changes of the glasses were investigated by Raman and infrared spectroscopy. As Fe2O3 increases, the structural change is attributed to the significant effect of Fe3+ ions on the phosphate network in the glasses. The thermal behaviors of the glasses were studied by DSC methods. As Fe2O3 gradually replaces Al2O3, the crystallization tendency of these glasses increases. The chemical durability of the glasses is assessed by measuring the dissolution rate. As the Fe2O3 content increases, the overall trend of the chemical durability is first lowered and then increased. The conductivity of the glasses varied greatly with the Fe2O3 content in the frequency range used. The activation energy (Eac) decreases from 59.8 to 45.7 kJ mol−1 with increasing Fe2O3 content.

P2O5-added Li2O-SiO2-Si3N4 glasses were prepared by melt-quenching the liquid inside a glove box under a N2 atmosphere. Studies on crystallization kinetics of the glasses show that the crystallization of oxynitride glasses is controlled by the three-dimensional interfacial growth mode of crystals (Avrami index = 2.70–3.90). The introduction of the nucleating agent P2O5 can increase the crystallization ability, and the crystallization activation energy is reduced. X-ray diffraction and scanning electron microscope were used to investigate the crystallization behavior and phase formation of the glass-ceramics. In general, the addition of 3.0 mol% nucleating agent P2O5 and two-step heat-treatment facilitate the precipitation of rod-like Li2Si2O5 crystals with high aspect-ratio, which are uniformly embedded in the glass matrix and show interlocking and uniform morphology, thereby improving the mechanical properties of Li2O-SiO2-Si3N4 oxynitride glass-ceramics. This work provides a roadmap for the preparation of high performance glass-ceramics.

This study focused on the glass forming, crystallization, and physical properties of ZnO doped MgO-Al2O3-SiO2-B2O3 glass-ceramics. The results show that the glass forming ability enhances first with ZnO increasing from 0 to 0.5 mol%, and then weakens with further addition of ZnO which acted as network modifier. No nucleating agent was used and the crystallization of studied glasses is controlled by a surface crystallization mechanism. The predominant phase in glass-ceramics changed from α-cordierite to spinel/gahnite as ZnO gradually replaced MgO. The phase type did not change; however, the crystallinity and grain size in glass-ceramics increased when the glasses were treated from 1030 °C to 1100 °C. The introduction of ZnO can improve the thermal, mechanical, and dielectric properties of the glass-ceramics. The results reveal a rational mechanism of glass formation, crystal precipitation, and evolution between structure and performance in the xZnO-(20-x)MgO-20Al2O3-57SiO2-3B2O3 (0 ≤ x ≤ 20 mol%) system.

Novel Li2O-La2O3-ZrO2-P2O5 glass ceramics were successfully prepared by a mechanical ball-milling method and followed by a heat-treatment process. Composition of the glass ceramic electrolytes and the heat-treatment process were optimized by physical characterization and electrochemical measurements. The results show that, the main crystal phases of all the obtained glass ceramics are LiZr2(PO4)3, and the secondary crystal phases are LaPO4. Both the P2O5 content and sintering temperatures have little effect on the composition of the crystal phases, but have a great influence on the microstructure. Electrochemical impedance spectroscopy (EIS) shows that the P2O5 content has a greater influence on the ionic conductivity of the glass ceramics than the sintering temperature. With the increase of P2O5 content, the activation energy of lithium-ion conduction decreases first and then increases in the range of 0.40–0.49 eV. The sintering temperature has a great influence on the chemical stability and has little effect on the electrical conductivity of glass ceramics. In particular, the 30.3Li2O-8.7La2O3-26.0ZrO2-35.0P2O5 glass ceramic exhibits good chemical stability upon exposure to aqueous solutions.

In this contribution, we presented a systematical investigation and prepared partially vitrified ceramic foam materials using polymetallic ore tailings (POTs) and other waste as raw materials. More importantly, six different POTs were evaluated in terms of bloating behavior, besides, the effects of sintering temperature and fly ash (FA) content on the structure, physical-mechanical properties and chemical stability were investigated. Our results revealed that among all selected POTs, the BT2 sample exhibits the best bloating ability due to the formation of appropriate liquid content, which is favorable for forming stable pore structure. Increased sintering temperature can accelerate the liquid phase formation and the increase in pore size, resulting in higher porosity and lower bulk density. And the pore structure varies with the addition of FA relatively uniform pore size distribution, high porosity and high compressive strength can be well achieved in this way. Besides, the partial vitrification of ceramic foam materials contributes to an increase in chemical stability while also reducing the risk of environmental pollutions. Here, an excellent performance combination (low bulk density at 0.63 g/cm3, high porosity at 73.6%, high compressive strength at 9.1 MPa) can be obtained in an optimized condition (15 wt% FA additions, sintering temperature at 1120 °C). The finding in this work, we believe, would provide guidance for rational utilization industrial wastes, which based on the synergistic complementarity effect between chemical components.

Generally, glass-ceramics possess better properties than their parent glasses. Here, we successfully prepared Sr2+/Y3+ co-doped MgO-Al2O3-SiO2-based glasses and transparent glass-ceramics. The results revealed that the glass stability for the parent glasses increased and then decreased as the SrO content increased, showing the opposite trend of crystallinity under the same heating conditions. Structurally, the bonding strength between the structural groups showed the same trend as the glass stability. In addition, the main crystalline phases in the glass-ceramics were cordierite (Mg2Al4Si5O18), magnesium aluminum silicate (Mg2Al4Si5O18) and strontiumosumilite (Sr0.91Mg2(Al5.82Si9.18O30)). Regarding the microstructures of the glass-ceramics, spherical or near-spherical grains appeared. As for the physical properties of the glass-ceramics, the density initially increased and then decreased, while the molar volume followed the opposite trend with the increasing SrO concentration. Analysis of the mechanical properties showed that the Vickers hardness, bending and compressive strength of the glass-ceramics first decreased and then increased with the variation of the SrO and Y2O3 contents.

Novel porous CaO-Al2O3-SiO2-Si3N4 glass-ceramics with in-situ grown rod-like β-Si3N4 crystals were fabricated by sintering under a nitrogen atmosphere. Sintering behavior, microstructures and mechanical properties of various compositions in the CaO-Al2O3-SiO2-Si3N4 system were investigated, using differential scanning calorimeter (DSC), X-ray diffractometry (XRD) and scanning electron microscopy (SEM) methods, followed by physical and chemical property measurements. Depending on our experiments, the coexistence of CaO-Al2O3-SiO2 glass and α-Si3N4 can lower the phase transition temperature of α-Si3N4 and promote the in-situ formation and growth of β-Si3N4 grains during sintering process. The in-situ grown rod-like β-Si3N4 grains in the glass-ceramics are useful to the improvement of physical and chemical properties by addition of α-Si3N4 to the system. This was attributed to that the in-situ grown β-Si3N4 grains formed a spatial inter-locking microstructure. The physical and chemical properties of the porous glass-ceramics are mainly determined by the β-Si3N4 content, the porosity and the residual glassy phase. The porous CaO-Al2O3-SiO2-Si3N4 glass-ceramics with high porosity, high mechanical strength and low dielectric constant were obtained, indicating it is potential high-temperature industrial applications.

In this work, alkali-free B2O3-Al2O3-SiO2 glasses containing alkaline-earth metal oxides were prepared by conventional melt-quenching method. Influence of Y2O3 substitution for B2O3 on the structure and properties of the glasses was systematically discussed. The structural variations of the glasses doped with different Y2O3 content were studied by FT-IR spectroscopy. Simultaneously, the relationship between the structure and related properties of the glasses including density, thermal expansion coefficient, strain point, compressive strength, bending strength, Vickers hardness, chemical durability and light transmittance was also investigated. The study on FT-IR spectra shows that Y2O3 acts as a network modifier and destroys the glass network structure. In terms of the properties of the glasses, with the increase of Y2O3 content at the expense of B2O3, the density and thermal expansion coefficient increase, while the chemical durability and transmittance decline. In addition, the compressive strength and bending strength decrease first and then increase, but the replacement of Y2O3 has less effect on the strain point and Vickers hardness. Each of the designed glasses possesses good transmittance (above 80%), very high strain point (near 732 °C) and excellent chemical durability.

Glass-ceramics materials of SrO-BaO-Nb2O5-B2O3 system have been prepared by conventional melt-casting followed by controlled crystallization. The crystallization kinetics, phase evolution, microstructure, breakdown strength and dielectric properties have been explored by differential scanning calorimetry (DSC), X-ray diffractometer (XRD), scanning electron microscope (SEM), and multifunction LCR meter. The results reveal that crystallization mechanism of this glass is believed to be three-dimensional interfacial growth. It was observed that predominant crystalline phase is Ba0.39Sr0.61Nb2O6 in these glass-ceramics crystallized at 750 °C, and the grain size increases with increase in crystallization time. The uniform microstructure can be seen clearly in glass-ceramics crystallized at 750 °C for 3 h, and the obtained glass-ceramics was found to possess optimal properties. Moreover, glass-ceramic with a dielectric constant of 58, the dielectric loss of 0.007 and breakdown strength of 1010 kV/cm could be achieved. In addition, energy storage density of glass-ceramics reached a maximal value of 2.62 J/cm3. To our knowledge, studies on SrO-BaO-Nb2O5-B2O3 glass-ceramics without SiO2 as a glass network former are few, and the melting temperature of the B2O3-based glass is lower than that of SiO2-based glass, which is conducive to the purpose of energy saving. These findings indicate that this glass may be a candidate for high energy-storage capacitors.

Study of 20MgO-20Al2O3-57SiO2 (MAS) glasses occupies a crucial position for optimizing glass performances for industrial applications. Here, we employed Cr2O3 dopant, and successfully prepared series of 20MgO-(20-x)Al2O3-57SiO2-3B2O3-xCr2O3 (MASBC) glasses with a doping level, denoted by x, ranging from 0 to 1 mol%, by conventional melt-quenching method. The investigation was systematically conducted using DSC, XRD, IR, optical absorption, electron paramagnetic resonance (EPR) and luminescence techniques. Structural analysis shows that all glass samples are amorphous in nature, and the glass network was mainly identified as the functional groups of [SiO4] and [AlO4]. From the optical absorption data, various optical parameters such as optical band gap, Urbach energy, crystal field and Racah parameters can be obtained. Besides, the luminescence and excitated spectra were recorded to confirm the presence of Cr3+ in a weak crystal field, and the luminescence lifetime was found to decrease with increased Cr2O3 due to the dipole interaction between the Cr3+ pairs (Cr3+-Cr3+). The EPR spectra of Cr2O3-doped MASBC glass exhibit two resonance signals at g = 5.33 and 1.96, indicating the characteristic of Cr3+ ions. Subsequently, according to the calculated bonding parameters, we confirm a strong ionic character of glass samples.

Generally, highly crystalline transparent glass-ceramics possess excellent physical and chemical properties compared to organic and other inorganic optical materials. We have successfully prepared highly crystalline transparent glass-ceramics in the MgO-Al2O3-SiO2 system by "extreme-time" nucleation & "finite-time" crystallization processes using P2O5, ZrO2 and TiO2 as multiple nucleating agents. The results revealed that the crystallization of glass is controlled by a three-dimensional interfacial crystal growth process. These glass-ceramics mainly consisted of cordierite crystals with a residual glassy phase, and crystallinity increased with crystallization time, but light transmittance decreased with crystallization time due to enlarged grain sizes. EDS mapping revealed a uniform distribution of elements within the glass-ceramic. In the optimal preparation condition (825 °C/96 h + 990 °C/3 h), these glass-ceramics exhibited a high crystallinity (87.3 vol. %), high transmittance (78%), and excellent mechanical properties. This work provides a roadmap for preparing highly crystalline transparent glass-ceramics for applications in optical engineering.

In the direction of dealing with solid hazards, preparing glass ceramic foam materials has become a practicable technique due to its environmental-friendly and economical characteristic. Here, we have successfully prepared glass ceramic foams with excellent combination of properties by utilizing lead-zinc mine tailings (LZMT), fly ash (FA) and red mud (RM) as the major component. The influence of sintering temperature on phase evolution, pore morphology, microstructure, physical properties and chemical stability of glass ceramic foam was investigated. The results reveal all above performances exhibit temperature-dependent character, with increasing sintering temperature, the performances enhance first and then deteriorate, the optimal porosity and compressive strength value for the prepared sample can be well achieved at the temperature of 980 °C. Liquid phase was formed during the heat treatment process and resulted in the variation of pore structure. According to SEM image and EDS spectra, the liquid phase may be the Ca-Al-Si-O system glass with less network modifier. The experiment results indicated that glass ceramic foams can be obtained by using solid wastes with different chemical compositions, better yet, it features with economic efficiency to solve the industrial solid wastes problems.

MgO-Al2O3-SiO2-B2O3 system transparent glass-ceramics have been prepared by conventional melt-quenching method followed by controlled crystallization, and their properties were also studied. The crystalline phases, crystal morphology, physical and light transmittance properties of glass-ceramics were characterized by DSC, XRD, FTIR, FE-SEM, thermo-mechanical analyzer and UV spectrophotometer. The results indicated that the crystal phase μ-cordierite turned to α-cordierite with increase in heat treatment temperature, and cordierite nanocrystals with size less than 50 nm were precipitated from the matrix glass, which was confirmed by the X-ray and SEM results. It is observed that the main elements in the glass-ceramics are uniformly distributed from EDS element distribution maps. The light transmittance of glass-ceramics obviously decreases with rising of crystallization time. All things considered, when the parent glass was crystallized at 1045 °C for 1 h, the prepared glass-ceramics possesses good light transmittance (76 %), lower density (2.498 g/cm3), lower thermal expansion coefficient (2.469 × 10− 6/°C), higher bending strength (167 MPa), compressive strength (376 MPa) and higher Vickers hardness (7.8 GPa). The combination of excellent mechanical, thermal and optical properties makes this family of transparent glass-ceramics showing potential applications.

Barium strontium niobate (BSN) ceramics with different amounts of BaO–SrO–Nb2O5–Al2O3–B2O3–SiO2 (BSNABS) glass additive were prepared via the conventional solid-state sintering method, and their sintering behavior, microstructure, electric properties and energy storage properties were systematically investigated. It was found that the addition of BSNABS glass could significantly lower the sintering temperature, refine the grain size and enhance the breakdown strength of ceramics. Meanwhile, the reduction of the dielectric constant for BSN ceramics was slowed down due to the precipitation of ferroelectric phase BSN and BaAl2Si2O8 from the glass during the sintering process. In addition, impedance spectra results showed that high grain boundary resistance was the main reason of the enhancement for breakdown strength. The sample with 4 wt% glass addition possessed the highest breakdown strength of 240 kV/cm, the maximum energy density of 0.982 J/cm3 and the energy efficiency of 76.5%, which may be used as a suitable candidate ceramic material for high energy storage density capacitor.

This study focused on the effect of partial substitution of Ta2O5 by Nb2O5 on the glass formation, structure and electrocial properties of Li2O-Ta2O5-ZrO2-SiO2 glasses. Structural analysis showed that Nb5+ enters the glass matrix in the form of NbO6 octahedra. When the content of Nb2O5 is 2.94 mol%, Nb5+ ions disrupt the silicate lattice and act as network modifiers. When the content of Nb2O5 is 5.88 and 11.77 mol% , Nb5+ ions play the role of glass formers, forming a three-dimensional chain lattice by interconnecting the NbO6 octahedra with different deformations. Among all the glass samples, the glass containing 5.88 mol% Nb2O5 has the maximum ionic conductivity of 1.066 × 10−6 S /cm at 250 °C, which is an order of magnitude greater than the ionic conductivity of the matrix glass. These glass samples have the potential to be used as solid electrolytes in electrochemical applications.

The effect of various alkali metal content (Li, Na) in high-alumina-silicon cover glass on the structure and performance of the glass is investigated in this work. The findings of the performance investigation show that the density, chemical stability, and thermal expansion coefficient of glasses display nonlinear changes. In addition, the typical thermal and dielectric properties are unaffected by combined alkali. The integrity of the glass network structure and the tightness of ions alternately vary due to the influence of lithium ion's own features, which is origin of MAE according to the results of XPS and infrared spectroscopy. It is certain that altering the Li/Na ratio can optimize this type of glass, and the defined range has guiding relevance for the design and production of cover glass.

The Fe2O3-doped magnesium aluminosilicate-based glasses were prepared by the traditional melt quenching method. The effects of Fe2O3 on the structure and properties of the prepared glasses were analyzed. DSC results indicate that the crystallization peak temperature is increasing first and then decreasing with Fe2O3 doping, and the thermal stability gradually decreases. Infrared spectrum curve illustrates that with increasing Fe2O3 content, the glass network is destroyed, and the number of non-bridging oxygen increases, resulting in a decrease of the optical band gap energy and an increase of the Urbach energy. In ultraviolet-visible absorption spectra, two bands observed around 540 and 1035 nm are corresponded to the electronic transitions of Fe3+ from 6A1g to 4T2g and Fe2+ from 5T2g to 5Eg, respectively. The obtained chromaticity coordinate parameters indicate that the prepared Fe2O3-doped magnesium aluminosilicate-based glasses can be applied to the fluorescent material of the light conversion layer of blue light-emitting diode device.

Li 6.5 La 3 Zr 1.5 Nb 0.5 O 12 (LLZN) garnet-type structure was synthesized at low temperature with B 2 O 3 addition by solid state reaction method. The effects of B 2 O 3 content on the formation, microstructure, ionic conductivity and activation energy of the LLZN solid electrolytes have been investigated by X-Ray diffraction (XRD), scanning electron microscopy (SEM) and alternate current (AC) impedance spectroscopy. The cubic LLZN phase was obtained after calcining at 850 °C for 6 h and no phase evolution was observed after sintering at 1100 °C for 6 h. The relative density and lithium ion conductivity increased first and then decreased with increasing B 2 O 3 content, reaching the maximum value of 92.4% and 1.86×10 −4 S cm −1 respectively in the sample with 1.4 wt% B 2 O 3 . By contrast, the activation energy reached a minimum value of ~31.5 kJ mol −1 .

Novel ultra-low temperature co-fired ceramic composites consisting of BaTiO3 and BaO–ZnO–Bi2O3–B2O3 (BZBB) glass were successfully produced under 500 °C, and their sintering behavior, phase composition, microstructure and dielectric properties as functions of sintering temperature were investigated. The XRD and SEM results showed that there was no reaction between the glass and the ceramic but the Bi24B2O39 was formed in all samples during sintering process. This indicates that the BZBB glass not only acts as sintering aids but also involves in crystal phase formation. The composites with 60–90 wt% of BZBB glass frit could be densified at a sintering temperature of 450 °C for 30 min, and exhibited widely adjustable dielectric constant (35–133) and acceptable dielectric loss (

The porous ceramics were prepared by directly sintering of lead-zinc mine tailings and fly ash as the raw materials without any additional sintering and foaming agent. The effects of fly ash addition on the crystalline phases, pore structure, physical–chemical porosities and mechanical strength were investigated. The results showed that the bulk density decreased firstly and then increased while the porosity and water absorption presented the opposite tendency with the increase of fly ash content. Meanwhile, the chemical stability improved and the flexural strength had the same variation tendency of the bulk density. The phase evolution of sample with 60 wt% fly ash addition indicated that anorthite phase was formed at low temperature (1000 °C). The thermal behavior illustrated that the foaming process was initiated by the reaction of internal constituents in the lead-zinc mine tailings. Different pore structures indicated different foaming mechanisms that probably occurred at different temperatures. The porous ceramics with 60 wt% fly ash addition exhibited excellent properties, including bulk density of 0.93 g/cm 3 , porosity of 65.6%, and flexural strength of 11.9 MPa.

The effects of SnO2 content on the structure, fining, physical and chemical properties of the glasses were systematically discussed. The analytical results of Fourier transform infrared (FT-IR) spectra and X-ray photoelectron spectroscopy (XPS) show that the structure of non-alkali aluminoborosilicate glasses became loose firstly and then compact with the increase of SnO2 content. The appropriate addition of SnO2 can reduce the number of bubbles and has a positive impact on the glass properties. Simultaneously, the relationship between the glass structure or fining effect and the density, molar volume, Vickers hardness, compressive strength, bending strength, glass transmittance, and chemical stability was discussed. With the increasing of SnO2, the density shows an increasing trend, while the molar volume, compressive strength, bending strength, and transmittance increase first and then decrease decline for the studied glasses. In addition, the Vickers hardness and chemical stability decrease first and then increase.

Generally, safety and environmental friendliness have been the major factors for the wide application of waste-based ceramic materials. Vitrified ceramic materials have an outstanding ability to solidify heavy metal ions, which may become a potential product for recycled waste. However, the role of different types of heavy metal ions in waste-based vitrified ceramics is not clear, as well as their stabilization behavior. Hence, electrical insulators waste and red mud-based porous semi-vitrified ceramics are prepared and used as host materials to investigate the influence of heavy metal ions (different types and contents) on the phase composition, pore structure and physical-mechanical performance of the prepared samples, including the stabilization behavior and mechanism of heavy metal ions. The obtained results show that the added three heavy metal ions can act as modify ions and lead the softening temperature of samples to decrease, resulting in the obvious variations in the structure and performance of the prepared samples. The stabilization behavior illustrates that the added heavy metal ions are selectively solidified in the glassy phase (solidifying Cd2+) and crystalline phase (solidifying Cu2+ and Zn2+) of the prepared samples, causing its leaching rate to be much lower than the regulatory standard limits. Moreover, the formed “gas-liquid-solid phase” structure can effectively protect the solid matrix from the corrosion of the acidic solution, ensuring that heavy metal ions are well kept in the matrix, even under acidic conditions. The results illustrated that the stabilization of different types of heavy metal elements is selective, providing theoretical support for the safe application of waste-based porous semi-vitrified ceramics which can be used as a competitive eco-friendly construction material.

In this paper, the effect of boron-aluminum anomaly on the structure-performance of alkali-free glass substrates is investigated, aiming to provide key guidance for the optimization and transformation of display devices. Mainly using XPS, infrared, glass modeling and performance analysis, the survey results show: As the substitution of B2O3 for Al2O3 reaches 8wt%, the boron-aluminum anomaly appears (3B→4B, 4Al→6Al), causing extremum of performance to occur. The whole process also affects the Qn family, as the coordination number of B and Al points to 4, the Qn family is more inclined to Q4, and vice versa. Moreover, the coordination status of B and Al does not completely follow the RO/Al2O3 ratio due to the secondary polarization of O2− caused by the high field strength of R2+. The glass obtained in this study basically meets or even far exceeds the requirements of substrate usage, which has certain referenced significance for the actual display industry.

A series of Gd2O3–Ga2O3–SiO2 (GGS)-based glasses doped with Nd2O3 were prepared by a conventional high-temperature melting-quenching method. The effect of Nd2O3 doping on the physical and luminescence properties was investigated and the preliminary research on crystallization behavior was also studied. The obtained results showed that the density and refractive index of the prepared GGS-based glasses increased with increasing Nd2O3 content. In the range of 400–900 nm, eight absorption peaks were observed in the Nd2O3-doped GGS-based glasses and the absorption intensity is enhanced with the increase of Nd2O3 content. Three emission peaks ascribed to the transitions from 4F3/2 to 4I9/2, 4I11/2, 4I13/2 at 898, 1057, 1330 nm were observed, respectively. The fluorescence emission intensity increased steeply when Nd2O3 concentration changed from 0.5 to 3.0 wt% and then decreased with the further increment of Nd2O3. Based on the analysis of Judd-Ofelt theory, the spectroscopic quality factor changed from 0.747 to 0.860 with the increase of Nd2O3 content, and the emission transition of 4F3/2 → 4I11/2 centered at ~1057 nm had a higher stimulated emission cross section (2.409–2.881 × 10−20 cm2), which has the potential to be used as a high-power laser (1.06 μm) output medium. The results of crystallization behavior indicated that the adjustment of glass composition or heat treatment schedule could help to obtain the transparent glass-ceramic. The prepared Nd3+-doped GGS-based glasses have the optimal fluorescence performance, which can be used as a potential solid-state optical functional material.

Significant safety problems and poor cyclic stability of conventional lithium-ion batteries, which based on organic liquid electrolytes, hinder their practical application, while all-solid-state batteries (ASSBs) are considered the most promising candidates to replace traditional lithium-ion batteries. As a critical component of ASSBs, solid-state electrolytes play an essential role in ion transport properties and stability. At present, the solid garnet electrolyte is considered as one of the most promising electrolytes because of its excellent performance. However, it still faces many challenges in ionic conductivity, air stability, electrode/electrolyte interface, and lithium dendrites. Therefore, this review is concerned about the up-to-date progress and challenges which will greatly influence the large-scale application of solid garnet electrolytes. Firstly, various ways to improve the ionic conductivity of solid garnet electrolytes are comprehensively summarized. Then, the stability of solid garnet electrolytes in the air is carefully discussed. Secondly, the latest progress in interface engineering between anode/cathode and solid garnet electrolytes treated by different methods is reported. The formation mechanism and influencing factors of lithium dendrites in the solid garnet electrolyte are systematically focused on. Finally, the development and innovation of composite solid garnet electrolytes and 3D garnet electrolytes are summarized in detail. Some important characterization techniques for studying the aforementioned problems are also summarized. Based on the current development of solid garnet electrolytes and solid-state batteries, further challenges and perspectives are presented.

Li-Al-P-O-N glasses containing AlN have been successfully prepared by melting batches at 1100–1150 °C under N 2 atmosphere in a Si-Mo-heated resistance furnace. La 2 O 3 was introduced in order to improve ionic conductivity of the Li-Al-P-O-N glasses. The amorphous nature of these samples was verified by an X-ray diffractometer. The effects of partial substitution of La 2 O 3 for Al 2 O 3 on the properties such as density, glass transition temperature, the crystallization temperature, chemical stability and ionic conductivity were investigated. At the same time, the relationship between these properties and the structures of the glasses were discussed. The structural network of the glass series is not greatly changed by small addition of La 2 O 3 content. The introduction of La 2 O 3 into Li-Al-P-O-N glasses enhances the ionic conductivity but decreases slightly the chemical stability, which has a potential application as Li + solid electrolyte materials.

Ceramic foams were prepared by powder technology using lead–zinc mine tailings, red mud and silica sand as the major component, Na2B4O7 as the flux agent. The influence of the sintering temperature on the phase evolution, pore morphology, bulk density, water absorption, porosity, thermal conductivity, mechanical properties and chemical stability was studied. The experimental results showed that a process of desulfurization was observed. With increasing sintering temperature, the bulk density decreased while the porosity and the water absorption both increased. The SEM images showed that larger pores and smaller pores were formed at high temperature. These differences may be caused by the different foaming mechanisms. The thermal conductivity of samples decreased and later increased and the bending strength decreased with increasing the sintering temperature. Based on these results, the sample sintered at 970 °C had a bulk density of 0.56 g/cm3, a porosity of 76.2%, a bending strength of 5.3 MPa and a thermal conductivity of 0.21 W/(m K). Furthermore, because of its high porosity and lower thermal conductivity, the ceramic foams prepared in this work would be suitable for thermal insulation in the building industry.

Transparent cordierite-based glass-ceramics with high crystallinity were prepared successfully. The crystallization kinetics of parent glass was deeply investigated by differential scanning calorimetry (DSC). After heat-treatment at 1030 °C for 6 h, a large amount of α-cordierite (indialite) crystals devitrified from the parent glass, which was confirmed by the X-ray diffraction and TEM results. The crystallinity of the obtained transparent glass-ceramics reached up to 87.5%, which can be ascribed to the composition and heat treatment of parent glass. The high transparency of glass-ceramics mainly resulted from the small difference of refractive index between α-cordierite and the parent glass. In addition, these transparent glass-ceramics possessed low density (2.477 g/cm 3 ), low thermal expansion coefficient (1.435×10 −6 °C −1 ) and high Vickers hardness (8.1 GPa). The combination of excellent physical, thermal and optical properties makes this new family of transparent glass-ceramics exhibiting potential applications in the fields of base materials for rare-earth ions.

The preparation of high-performance ceramics using industrial waste as raw materials is an important direction in the comprehensive utilization of waste residue. In this paper, we used silica sand tailings and other industrial waste as raw materials to prepare two types of full waste-based ceramic materials without additional agent. The results showed that different waste ratios caused the variation in content and composition of glassy phase formed in the full waste-based material, leading to the formation of internal structure in different ceramic materials. Especially, the composition of glassy phase formed in ceramic foams was transferred from Ca–Al–Si–O to Al–Si–O glass system, resulting in the difference in pore structure and performance. This work provides a way to design the composition and control the properties of materials by using coupling reactions between chemical components during the material preparation, achieving high value, high efficiency and safe use of waste resources.

MgO-Al2O3-SiO2 (MAS)-based glass-ceramic has excellent properties and is gradually being used in the field of new functional materials. Here, we investigated the crystallization progress (the evolution of crystalline phase and microstructure), luminescence and mechanical properties of MAS-based glass-ceramic with Cr2O3 doped. The obtained results show that the glass stability decreases gradually with increasing Cr2O3 content. Structurally, the predominant phase in glass-ceramics varies from α-cordierite to spinel, mullite and sapphirine-2 M. The analysis of crystal field parameters confirms that the added Cr3+ ions located in a strong crystal environment and explains the appearance of the sharp peak at 690 cm−1 and long decay time. The prepared sample with 0.15 mol% Cr2O3 has low bulk density and high mechanical performances. We therefore show that a few Cr2O3 dopants have positive effects on both luminescence and physical behavior, which is great importance for tuning MgO-Al2O3-SiO2 based glass-ceramics in optical device applications.