Glass Crystallization Research Articles

Microstructure, Dielectric Properties and Bond Characteristics of Lithium Aluminosilicate Glass-Ceramics with Various Li/Na Molar Ratio

The advent of 5G technology presented new challenges regarding the high-frequency characteristics of electrical signals and their impact on the cover glass properties of electronic devices. This study aimed to analyze the effect of the Li/Na molar ratio on the dielectric and mechanical properties, as well as the structural characteristics, of lithium aluminosilicate glass-ceramics. Using the melting method, we prepared lithium aluminosilicate base glasses and subsequently crystallized them by adjusting the molar ratio. XRD and TEM analyses were employed to investigate the resultant structures and crystal formation in the five base glasses. It was observed that Li2Si2O5 and LiAlSi4O10 crystals precipitated, exhibiting varying degrees of crystallinity and crystal ratios. Through a comparison of dielectric properties before and after crystallization, it was found that the dielectric constants of the glass-ceramics were consistently reduced. This decrease can be attributed to the lower dielectric constants exhibited by both crystalline phases compared to the parent lithium aluminosilicate glasses. Furthermore, the presence of glass crystals effectively immobilized the alkali metal ions within the glass phase, impeding their movement under an electric field. Consequently, the dielectric loss value of the glass-ceramics decreased with the increasing amount of precipitated crystals. By carefully adjusting the composition and optimizing the crystallization process, we successfully produced lithium aluminosilicate glass-ceramics, demonstrating excellent mechanical and optical properties, coupled with low dielectric properties.

Calorimetric studies of yttrium doped non-conventional phase-change materials for improved performance

Though phase-change materials (PCMs) are regarded as constituent part of next-generation phase-change memory and other unfolding optoelectronic applications, the kinetics study of glass transition and crystallization, significant property in switching remains obscure in high-temperature region. Hence, this paper reports the investigation of glass transition and crystallization kinetics of Te(1-x) (GeSe0.5)Yx (TGSY) chalcogenide glass using differential scanning calorimetry (DSC) at heating rates 5, 10, 15, 20 °C/min. The effect of increasing Y quantity has been described by connecting structural relaxation kinematics during glass transition phenomena and devitrification while crystallization in chalcogenide glasses with their varied physicochemical characteristics. The inclusion of Y causes a discernible rise in the crystallization rate. The system is compatible with a strong glass-forming liquid, according to the Te(1-x) (GeSe0.5) Yx material fragility index. According to the average values of the kinetic exponent factors, there is heterogeneous nucleation for the investigated composition, which is subsequently followed by a two- or three-dimensional crystal growth phenomenon. Different glass stability criteria have been discussed based on the relationship between the characteristic temperatures. The CZW and CLX criteria were found to be inappropriate for discussing glass stability (GS) for the studied compositions based on the heating rate and composition dependencies of all criteria. The CYL criteria of Yuan et al. is the finest and it demonstrates the optimal ability for evaluating the GS, according to the data that was extracted from several GS criteria and their relative change parameters. By adding Y, thermal stability parameter and enthalpy emitted during the transition of glass and crystalline phases have been found to have an inverse relationship. All studied properties can conclude the application of studied material in phase-change material devices.

Trace element partitioning in strongly peraluminous rare-metal silicic magmas – Implications for fractionation processes and for the origin of the Macusani Volcanics (SE Peru)

The Macusani Volcanics and related rocks (SE Peru) are well known examples of erupted strongly peraluminous rare-metal rich silicic magmas. We used the phenocryst/matrix glass method to determine relevant mineral/melt partition coefficients to facilitate modeling of such systems. Concentrations of trace (Li, Be, B, Al, P, Ti, Mn, Zn, Ge, Rb, Sr, Zr, Nb, Sn, Cs, Ba, La, Sm, Eu, Gd, Yb, Ta, W, Pb and U) and major elements were measured in obsidians, matrix glasses, glass inclusions, phenocrysts and phases from biotite reaction zones by Laser-Ablation ICP-MS and Electron Microprobe Analysis. The derived phenocryst/melt partition coefficients for quartz, plagioclase, sanidine, biotite, muscovite, andalusite and ilmenite are compared with values from reference silicic magmas and literature. Mineral/biotite partition coefficients are calculated for tourmaline and hercynite. The database is then applied to model chemical fractionation in Macusani magmas. Fractional crystallization and partial melting trends (with the B concentration used as a proxy for the fraction of residual liquid) generate progressively more evolved (higher Rb, Nb, Sn, Cs and Ta and lower Sr, Ba and Pb) residual liquids. The trace element concentrations in obsidians are reproduced for 50–70% crystallization of matrix glasses from ash-flow tuffs. This demonstrates that differentiation of magmas parental to the ash-flow tuffs can generate the highly evolved obsidian-forming liquids. Based on this, we present an updated model for crustal melting and the generation of the Macusani magmas. A metapelitic component dominates the source region but calcic plagioclase cores enriched in Sr, Ba and La suggest an affiliation with mafic magmas, which were likely potassic to ultrapotassic. The presence of a mafic component is consistent with the high heat fluxes in the source region and accounts for specific magmatic variables (i.e., middle crustal anatectic zone, very reducing fO2, high F). Petrogenetic processes differ significantly between Macusani Volcanics suites and two-mica leucogranites despite both having nearly identical source rocks, mineral assemblages and compositions.

Diffusion zone evolution around growing crystals in combeite glass

AbstractThe precipitation of nonstoichiometric crystals (of different composition from the parent glass) motivated us to study the stoichiometric Na2O·2CaO·3SiO2 ( N2CS3) glass‐forming system comprehensively. The concentration profiles of Na and Ca in the diffusion zone around Na4+2xCa4−x[Si6O18], , crystals in an N2C3S glass were characterized by energy‐dispersive spectroscopy and were then theoretically described. We show that the diffusion zone is formed because of the rejection of part of calcium by the growing crystal. The radial variation of the Ca concentrations and the crystal nucleation rate through the diffusion zone were analyzed simultaneously. We found that the nucleation rate in the diffusion zone near the crystal–glass interface drastically decreases due to the increase in the work of critical cluster formation resulting from the composition change. In contrast, the diffusion activation barrier remains practically constant. Moreover, the Ca diffusion coefficients, DCa, in Na2O·2CaO·3SiO2 and CaO·SiO2 glasses show the same Arrhenius dependence, demonstrating that (surprisingly) DCa does not depend on the glass composition in the CaO·SiO2–Na2O·SiO2 metasilicate joint. This work provides the quantitative spatial distribution of chemical components in a partially crystallized glass, shedding light on solid solution crystallization in a glass‐forming liquid and its consequences.

Interfacial alloying between lead halide perovskite crystals and hybrid glasses

The stellar optoelectronic properties of metal halide perovskites provide enormous promise for next-generation optical devices with excellent conversion efficiencies and lower manufacturing costs. However, there is a long-standing ambiguity as to whether the perovskite surface/interface (e.g. structure, charge transfer or source of off-target recombination) or bulk properties are the more determining factor in device performance. Here we fabricate an array of CsPbI3 crystal and hybrid glass composites by sintering and globally visualise the property-performance landscape. Our findings reveal that the interface is the primary determinant of the crystal phases, optoelectronic quality, and stability of CsPbI3. In particular, the presence of a diffusion “alloying” layer is discovered to be critical for passivating surface traps, and beneficially altering the energy landscape of crystal phases. However, high-temperature sintering results in the promotion of a non-stoichiometric perovskite and excess traps at the interface, despite the short-range structure of halide is retained within the alloying layer. By shedding light on functional hetero-interfaces, our research offers the key factors for engineering high-performance perovskite devices.

Modifying optical nonlinearities of ionic liquid crystal glass by adding gold and carbon nanoparticles

Future disruptive photonics technologies depend on the development of new types of nonlinear-optical glass composites containing nanoparticles. In this paper, we report the synthesis, structural characterization, spectral and nonlinear-optical properties of overlooked yet very promising glass nanocomposites made of glass forming ionic liquid crystals (cadmium caprylate) and two types of nanoparticles (gold and carbon). Nonlinear-optical properties of the prepared nanocomposites are studied by means of a standard Z-scan method and using visible (532 nm) nanosecond laser pulses. By exciting glass nanocomposites within their absorption band, an interplay between several nonlinear-optical mechanisms can be revealed. A simultaneous use of two types of nanoparticles (i.e. carbon and gold) enables a better control over effective optical nonlinearities of nanocomposites. More specifically, by changing an intensity of a laser beam, it is possible to vary the magnitude of the effective nonlinear refractive index and of the effective nonlinear absorption coefficient. In addition, even the sign of the effective nonlinear absorption coefficient can be changed. The proposed strategy to create novel nonlinear-optical materials using metal-alkanoates based glass-forming ionic liquid crystals and several types of nanoparticles will benefit rapidly growing nanophotonics and plasmonics technologies.

High capacity and aqueous stability immobilization of simulated trivalent actinides by zircon-based borosilicate glass-ceramics: Synergistic effect between the crystal lattice and glass network immobilization

The development of matrix with high capacity and stability immobilization of nuclear waste is highly desirable. Herein, new type of zircon-based borosilicate glass-ceramics (ZBGC) with high immobilization capacity and excellent aqueous stability was prepared and applied to immobilize simulated trivalent actinide (Nd). The effects of Nd doping and sintering temperature on the microstructure and phase composition of the obtained ZBGC were researched. The experimental suggested that high ZrSiO4 formation rate (97.49 wt%) was obtained by tuning the Nd content and sintering temperature. The record high immobilization capacity of Nd in ZGBC (18 at%) was achieved owing to the synergistic effect between the crystal lattice and glass network immobilization. Additionally, the obtained Nd-doped ZBGC exhibited excellent aqueous stability (∼10−6 g m−2 d−1) due to the high compactness. The results demonstrated that ZBGC with high immobilization capacity and aqueous stability could be potential matrix for actinides immobilization.

Crystallization in Ga–Sb–Se glasses and influence of the Se content

Crystallization in glasses composed of Ga, Sb and Se has been studied as a function of Se content. Six glass compositions are selected (Ga8Sb27Se65, Ga12Sb23Se65, Ga8Sb32Se60, Ga10Sb30Se60, Ga8Sb37Se55 and Ga8Sb40Se52), with different Se contents. Glass-ceramics are obtained by heating the glass 5 °C above its glass transition temperature. Glasses and glass-ceramics are characterized by differential scanning calorimetry, Raman spectroscopy, infrared spectroscopy and X-ray diffraction. A correlation between the Se content, the nature of the phase crystallizing and the electrical conducting properties of the material is evidenced. On one hand, antimony selenide Sb2Se3 crystallizes in over-stoichiometric and stoichiometric glasses compared to the x Ga2Se3 -(100-x) Sb2Se3 line. On the other hand, an unknown phase crystallizes in sub-stoichiometric glasses, followed by Sb2Se3. The resulting glass-ceramics are characterized by a conductivity reaching up to 2 S·cm−1, two order of magnitude higher than other Se-based glass-ceramics.

Perspectives on the impact of crystallization in bioactive glasses and glass‐ceramics

AbstractBoth unwanted and induced crystallization can impact bioactivity, physical and mechanical properties of bioactive glasses (BGs). Uncontrolled crystallization has negative consequences, rendering BGs unreliable. However, by manipulating the type, size, shape, and quantity of crystals in BGs, plenty of opportunities arise for controlling, for example, mechanical properties and degradability, leading to unique applications and improved performance. Understanding crystallization is a key step in developing bioactive glasses and glass‐ceramics (BGCs), and both fundamental and experimental research can aid in the design of BGCs for processing and biological function. In this perspective, we discuss the sources of crystallization and how controlled crystallization facilitates the functionalization of bioactive scaffolds, hybrids, coatings, composites, cements, and fibers.

Trehalose and sodium pyrophosphate inhibit ice-induced freezing quality deterioration of surimi: A comparative study on water migration, ice crystal growth, glass transition and state diagram

Trehalose and sodium pyrophosphate inhibit ice-induced freezing quality deterioration of surimi: A comparative study on water migration, ice crystal growth, glass transition and state diagram

Effect of substituting Na2O with B2O3 on the crystallization and properties of MgO–Al2O3–SiO2 transparent glass-ceramics

MgO–Al2O3–SiO2 (MAS) transparent glass-ceramics were prepared with ZrO2 as a nucleating agent, and the substitution of B2O3 for Na2O on the properties of the MAS glass-ceramics was investigated systematically. The results show that the substitution of B2O3 increased the glass transition temperature, crystallization temperature, and crystallization activation energy. Additionally, there was no change in the main crystal phase of the glass-ceramics, which were ZrO2 (JCPDS PDF#.50-1089) and Al0.52Zr0.48O1.74 (JCPDS PDF#.53-0294). The crystal growth mode shifted from three-dimensional growth to two-dimensional growth, and the crystal morphology transformed from a spherical appearance to a star-shaped appearance. Moreover, the mechanisms of the property changes induced by B2O3 substitution are revealed and discussed. The transmittance of MAS glass-ceramics without B2O3 decreased from 88 % to 32 % as the crystallization temperature increased from 800 °C to 920 °C, and decreased from 90 % to 8 % when B2O3 was added. Additionally, the Vickers hardness of MAS glass-ceramics decreased from 6.37 GPa to 6.13 GPa, after the introduction of B2O3, while, the fracture toughness increased from 1.48 MPa m1/2 to 1.55 MPa m1/2. The scratch behaviour of glass-ceramics exhibits a negative correlation with the applied load, but a positive correlation with the crystallization temperature. In particular, the incorporation of B2O3 substantially enhances the scratch resistance of glass-ceramics. The conclusions provide researchers with the roles of B2O3 in crystallization kinetics, microstructure, transmittance, and mechanical properties of MAS transparent glass-ceramics for various applications such as covers.

Glass‐ceramic: Controlled crystallization of glasses obtained from biomass ash

AbstractIn this work, vitreous material was produced, using ash from burning wood in a boiler, to obtain a glass‐ceramic with the gehlenite phase. The glass obtained by melt‐quenching at 1450°C was characterized by differential scanning calorimetry and other techniques to determine the glass transition and crystallization temperatures, and crystallization kinetics were investigated using the Kissinger model. Tablets prepared with glass powder were treated at 970, 990, 1074, and 1120°C for 1 h, to obtain the glass‐ceramic material. The phase identified by X‐ray diffraction was gehlenite, with two crystalline structures coexisting in the sample. According to the kinetics study, the phase with a tetragonal structure had a lower crystallization activation energy, and therefore, it may have been the first phase to be formed in the material. Scanning electron microscopy images revealed crystalline regions within the glassy matrix with a lamellar microstructure, with no geometrically defined morphology and no morphological or microstructural distinction, suggesting that both gehlenite phases coexist without apparent distinctions in the glass‐ceramic. The best results for water absorption, apparent porosity, and apparent density were for the glass‐ceramic sample sintered at 990°C, whose values were respectively 0.1, 0.29, and 2.89 g/cm3.

Impact of CaO addition on physico-chemical properties, crystallization, chemical durability and in vitro behavior of Na2O-ZnO-TiO2-P2O5 glasses

This work investigates the effect of CaO addition on physico-chemical properties, crystallization, chemical durability and bioactivity of phosphate-based glasses. To this end, five glass compositions in the system (40-x)Na2O-xCaO-10ZnO-20TiO2-30P2O5 with x = 0, 5, 10, 15 and 20 mol % have been elaborated by the conventional melt-quenching technique. Replacing Na2O with CaO oxide in the studied glasses increased remarkably the glass transition temperature Tg and density (ρ), while VM decreased with increasing CaO content indicating the high strength in the glass network. The existence of PO3 and PO4 units with P-O-P and P-O-Ti linkages in the glassy network was revealed by Infrared spectroscopy. The chemical durability was improved with increasing calcium content, indicating that replacing Na-O bonds with more covalent and stronger Ca-O bonds strengthen and crosslink the glassy network. The in vitro bioactivity of the two glass samples (x = 0 and 15 mol %) was studied using SBF solution. XRD, Infrared, ICP, and pH measurements proved the formation of a hydroxyapatite layer on the glass surface after interaction with the SBF medium, which is a crucial property of a potential bioactive glass. The correlation between XRD, Infrared, and ICP techniques indicated that glass containing calcium is more bioactive than free-calcium glass.

Phase formation during crystallization of melts and glasses of the GaxGe40-xS60 system

The purpose of this work is to study phase formation during quenching of glass-forming melts and crystallization of GaxGe40-xS60 glasses (x = 0–15 at.%), which are promising materials for optical IR glass-ceramics. The stability against crystallization of the glasses is determined to decrease with increasing gallium content. In the case of the glass-forming melts, the stability against crystallization increases in the range x = 0–8 at.% and then decreases. It is established that, during crystallization, not pure phases of binary sulfides are formed, but their solid solutions. When quenching the melts with a gallium content of 10–15 at.%, Ga2-xGexS3 solid solutions, which are isostructural to one of the polymorphic modifications of gallium sesquisulfide, are crystallized. Solid solutions form skeletal crystals, the growth of which leads to the formation of a dendritic crystal structure. Micro-liquation in the GaxGe40-xS60 glasses is observed.

Green biodegradable dielectric material made from PLA and electron beam irradiated luffa cylindrica fiber: devices for a sustainable future.

The growing prevalence of polymer-based plastics in the environment is an imminent risk to the natural world. As an immediate consequence of this, extensive research has been launched over the course of the past few decades in an effort to reduce the damage that manmade plastics cause to the natural environment. The current study attempts to explore the biodegradability of polylactic acid (PLA), a bio-compatible plastic, by incorporating small amount of electron beam irradiated natural fibers (2 to 10%) derived from luffa cylindrica (LC) at varying irradiation doses (0.5 Gy, 1 Gy, and 2 Gy). Natural fiber surface treatment using electron beam irradiation is effective and environmentally friendly. The biodegradation of composites was studied for 90 days in sand, soil, compost, brackish water, fresh water, salt water, and bacterial and fungal conditions. Maximum decomposition was observed in the composite sample (PLA/10% wt of LC fiber at 2.0 Gy) at 15.42% and 4.73% in bacterial and soil environments. X-ray diffraction (XRD) and Raman spectroscopy validated the fiber and PLAs crystallinity and molecular interaction. The derivative thermo-gravimetric curve (DTGA) showed that electron beam irradiation removed moisture, hemicelluloses, and lignin from hydrophilic fibers. The incorporation of LC fibers into the bio-composites resulted in an increase in the glass transition temperature (Tg), melting temperature (Tm), and crystallization temperature (Tc). Additionally, after LC fiber reinforcement, the composites' dielectric properties were enhanced.

Crystallization behavior and properties of quartz glass-ceramics synthesized from desert sand

Quartz glass-ceramics were synthesized with desert sand as the main raw material. The effects of pretreatment technology of desert sand and various cations on the glass stability (GS) parameters (KH, KLL,KW, KZW, KLX), crystallization kinetic parameters (crystallization activation energy (Ec), reaction rate (k), the effective frequency factor(ν) and the Avrami parameter (n)), phase transition, microstructure and properties of glass-ceramics were investigated. The results show that the chemical composition of desert sand is greatly changed by sieving and magnetic separation, and the glass stability, phase transition and crystallization ability of glass are controlled by the mixed mobile ion effect (MMIE), in which the ionic field intensity determined by ionic valence and radius plays a major role. Finally, the crystallization of glass is dominated by the surface crystallization mechanism, and the obtained glass-ceramics mainly consist of α-quartz, β-cristobalite and glass phases, which have excellent comprehensive properties.

Silicate glass fracture surface energy calculated from crystal structure and bond-energy data

We present a novel method to predict the fracture surface energy, γ, of isochemically crystallizing silicate glasses using readily available crystallographic structure data of their crystalline counterpart and tabled diatomic chemical bond energies, D0. The method assumes that γ equals the fracture surface energy of the most likely cleavage plane of the crystal. Calculated values were in excellent agreement with those calculated from glass density, network connectivity and D0 data in earlier work. This finding demonstrates a remarkable equivalence between crystal cleavage planes and glass fracture surfaces.

Multilayer, Broadband Infrared Reflectors Based on the Photoinduced Preparation of Cholesteric Liquid Crystal Polymers.

This paper focuses on preparing broadband reflective liquid crystal films through the diffusion of monofunctional and bifunctional monomers in a photoinduced trilayer system. By combining the hydrophilic and hydrophobic liquid crystal glass surface treatment technologies, the polymer network of polymer-stabilized cholesteric liquid crystal (PSCLC) itself serves as a diffusion channel to form a trilayer cholesteric liquid crystal composite system containing bifunctional monomers, a nematic liquid crystal composite system, and a cholesteric liquid crystal composite system containing monofunctional monomers. Utilizing the difference in the polymerization rates of monofunctional and difunctional polymerizable monomers, the monomers and chiral compounds diffuse relative to each other, so that the liquid crystal pitch exhibits a gradient distribution, and the broadened reflective width can reach up to 1570 nm. There is no doubt that new and improved processes and technologies offer important possibilities for preparing and applying PSCLC films.

Development of PLA/Lignin Bio-Composites Compatibilized by Ethylene Glycol Diglycidyl Ether and Poly (ethylene glycol) Diglycidyl Ether.

Poly (lactic acid) (PLA) is a promising green substitute for conventional petroleum-based plastics in a variety of applications. However, the wide application of PLA is still limited by its disadvantages, such as slow crystallization rate, inadequate gas barrier, thermal degradation, etc. In this study, lignin (1, 3, 5 PHR) was incorporated into PLA to improve the thermal, mechanical, and barrier properties of PLA. Two low-viscosity epoxy resins, ethylene glycol diglycidyl ether (EGDE) and poly (ethylene glycol) diglycidyl ether (PEGDE), were used as compatibilizers to enhance the performance of the composites. The addition of lignin improved the onset degradation temperature of PLA by up to 15 °C, increased PLA crystallinity, improved PLA tensile strength by approximately 15%, and improved PLA oxygen barrier by up to 58.3%. The addition of EGDE and PEGDE both decreased the glass transition, crystallization, and melting temperatures of the PLA/lignin composites, suggesting their compatabilizing and plasticizing effects, which contributed to improved oxygen barrier properties of the PLA/lignin composites. The developed PLA/lignin composites with improved thermal, mechanical, and gas barrier properties can potentially be used for green packaging applications.

Impact of PbO on structural, thermal, optical and gamma ray shielding behaviour of TeO2-CdO based glasses

A study was conducted to investigate the effect of an increase in the concentration of PbO on the structural, thermal, optical, and gamma ray shielding behavior of TeO2-CdO based glasses. The glasses were found to contain TeO4 and TeO3 units, as well as CdO metal oxide clusters, as indicated by the Raman spectrum. The glasses displayed minor weight loss (approximately 3%), suggesting high resistance to thermal degradation. With an increase in the concentration of PbO, the glass transition temperature (Tg), onset temperature (To), and crystallization temperature (Tc) all decreased. Additionally, the indirect band gap energy decreased from 3.497–3.337 eV as the lead oxide concentration increased. Moreover, the effects of PbO concentration on the linear attenuation coefficient (LAC) were investigated. The LAC values were found to be highest at 39.5 keV and decreased with increasing energy. As the PbO concentration increased, LAC values also increase. The Zeff displayed an inverse relationship with energy, except for an abrupt increase at 121.8 keV. The half value layer was found to be positively correlated with energy and varied with changes in PbO and CdO concentrations. The glasses demonstrated effective gamma radiation shielding properties, with the HVL remaining small even at higher energies, suggesting potential applications in industries such as medical imaging where thin shielding materials are preferred.