Glass Formation Research Articles

Utilizing Drug Amorphous Solid Dispersions for the Preparation of Dronedarone per os Formulations

Dronedarone (DRN), an antiarrhythmic drug, exhibits potent pharmacological effects in the management of cardiac arrhythmias. Despite its therapeutic potential, DRN faces formulation challenges due to its low aqueous solubility. Hence, the present study is dedicated to the examination of amorphous solid dispersions (ASDs) as a strategic approach for enhancing the solubility of DRN. Initially, the glass forming ability (GFA) of API was assessed alongside its thermal degradation profile, and it was revealed that DRN is a stable glass former (GFA III compound) that remains thermally stable up to approximately 200 °C. Subsequently, five commonly used ASD matrix/carriers, i.e., hydroxypropyl methylcellulose (HPMC), povidone (PVP), copovidone (PVP/VA), Soluplus® (SOL), and Eudragit® E PO (EPO), were screened for the formation of a DRN-based ASD using film casting and solvent shift methods, along with miscibility evaluation measurements. SOL proved to be the most promising matrix/carrier among the others, and, hence, was used to prepare DRN ASDs via the melt-quench method. The physicochemical characterization of the prepared systems (via pXRD) revealed the complete amorphization of the API within the matrix/carrier, while the system was physically stable for at least three months after its preparation. In vitro release studies for the ASDs, conducted under non-sink conditions, revealed the sustained supersaturation of the drug for at least 8 h. Finally, the use of attenuated total reflectance (ATR) FTIR spectroscopy showed the formation of a strong molecular interaction between the drug molecules and SOL.

The effect of composition on glass-forming ability, crystallization behavior, and soft magnetic properties of FeSiBCuNbNiCo amorphous/nanocrystalline alloys

The effect of composition on glass-forming ability, crystallization behavior, and soft magnetic properties of FeSiBCuNbNiCo amorphous/nanocrystalline alloys

Evading the refining-induced trade-off between performance enhancement and alloy composition deviation in Fe-based amorphous alloys

Understanding the slag-metal reactions in Fe-based amorphous alloys is of paramount importance to evade the refining-induced trade-off between performance enhancement and alloy composition deviation. In this study, the B2O3 and B2O3–CaO slags refining-induced alloy composition deviation was theoretically and experimentally verified in Fe83Si2B12P3 (at.%) amorphous alloy, and a quaternary SiO2–B2O3–CaO–Al2O3 slag suitable for FeSiBP amorphous alloy was designed after the careful calculation of slag-metal equilibrium, slag viscosity and melting point. After refining with simple B2O3 and B2O3–CaO slags, the enrichment of B element and depletion of Si element in the FeSiBP amorphous alloy was confirmed due to the oxidation of constituent Si element and the reduction of B2O3 in the slag. The refining-induced alloy composition deviation can be effectively alleviated by using our designed slags, and the 20%SiO2–55%B2O3–10%CaO–15%Al2O3 (wt.%) slag is effective in removing the impurities and enhancing the glass-forming ability (GFA). In terms of the removal of impurities, the high activity of B2O3 in slag is crucial for the oxidation and removal of Mn, Al, Ti impurities. These results are quite vital for the design of refining slags suitable for Fe-based amorphous alloys and pave the way for the large-scale production of high-performance soft magnetic materials.

Antifouling performance of TiO2-based SiO2–Na2O–K2O glass-ceramic coatings in marine environments

Biofouling refers to the accumulation of organisms on artificial surfaces. This phenomenon poses significant challenges in industrial processes, including reduced energy efficiency and increased fuel consumption. Antifouling coating systems are designed to prevent biofouling on artificial surfaces. Currently, there is a growing focus on developing eco-friendly solutions to mitigate the environmental impact of these antifouling coatings. In this study, the antifouling (AF) performance of a TiO2-based borosilicate glass-ceramic coating (Ti-GCC) system was evaluated in terms of barnacle settlement on the coating surface. To create anatase crystals in a coating, a special precursor glass (Ti-PG) formulation, Na2O–K2O–TiO2–B2O3–Al2O3–SiO2–P2O5–F, with <10 % of Na2O and 20 % TiO2 along with other components was used. The Ti-PG was characterised through X-ray fluorescence (XRF) spectroscopy to determine the chemical composition. The milled Ti-PG with additives was applied on a steel substrate using a spray gun and devitrified at 550 °C and 860 °C for 6 min. The phase determination, surface evaluation, thermal behaviour analysis, and AF evaluation of the Ti-GCC were conducted through X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), non-contact optical profilometry (NCOP), and thermogravimetric-differential thermal analysis (TG-DTA). The anatase crystal was determined to exist in the Ti-GCC structure. Although the AF evaluation results revealed that the Ti-GCC system had barnacle settlement (73.9 barnacles/cm2), the surface could be easily cleaned. Additionally, the EDS results confirmed that no biofilm was formed on the Ti-GCC's surface. The roughness of the surface before the AF evaluation and after the cleaning procedure was measured using NCOP, and the difference in surface roughness was examined. The small difference in the roughness of the surfaces suggested that the Ti-GCC system exhibited resistance to microbially induced corrosion (MIC). Furthermore, EDS mapping did not provide any evidence of barnacle diffusion into the coated layer. Furthermore, the thickness measurements of the cross-sectional area of the Ti-GCC before and after AF evaluation through SEM proved that coating depletion did not occur.

Glass formation processes in fullerene mixtures

The local structural features of the A20B80 fullerene mixture (where A = C60 and B = C70) are studied by the molecular dynamics simulations for a wide temperature range, including the phase of an equilibrium liquid phase and a supercooled melt, in order to elucidate the mechanism of formation of the icosahedral short-range order in binary molecular liquids. Structural and cluster analyzes revealed the presence of icosahedral clusters in the supercooled melt phase and determined the critical glass transition temperature.

Processes of Glass Formation in Fullerene Mixtures

Processes of Glass Formation in Fullerene Mixtures

Impact-related chemical modifications of the Chang’E-5 lunar regolith

Impact events on the Moon have been recognized as modifying the composition of surface materials through processes such as shock metamorphism and mixing with exotic components. Previous studies have indicated that the regolith sampled by the Chinese Chang’E-5 mission was primarily evolved from local mare basalts, likely originating from a single episode of effusive volcanism. The relatively simple and monotonic protolith of the Chang’E-5 regolith presents a unique opportunity to investigate the chemical modifications induced by impact events. In this study, we conducted detailed petrographic and mineralogical analyses on a diverse set of lunar regolith samples, including thirty-three small impact glass particles (39–227 μm), one large agglutinate (∼1.6 mm), and sixteen basaltic clasts (0.1–1.6 mm). Numerical modeling was also conducted to quantitatively assess the melting behavior of basaltic clasts under different impact conditions. Our primary objective was to evaluate the chemical variations of impact glass in relation to lithic clasts. While the majority of homogeneous impact glass spherules and larger basaltic clasts (≥1 mm) exhibit similar bulk compositions (e.g., Al2O3, CaO and FeO) to the local regolith, we recognize additional effects of impact processes, including impact comminution, impact melting and crystallization, differential volatilization, and potentially selective melting. These processes have modified the texture and geochemistry of lunar regolith components. The chemical signatures of small clasts in the Chang’E-5 regolith indicate that the fine size fractions (e.g., those with diameters of ≤ 300 μm) are predominantly composed of lithic and monomineralic fragments with a substantial proportion being dominated by mesostasis. Melting of these sub-millimeter fractions may lead to the formation of impact glass with chemical compositions deviating from the average local regolith. These results have implications for understanding the compositional evolution of the Chang’E-5 regolith. Notably, our study suggests that impact glasses spherules with different major (e.g., TiO2, MgO) and minor (e.g., REEs, Zr, Th and U) element compositions could be derived from the same protolith of local mare basalts, instead of being exclusively attributed to exotic impact ejecta. In this case, small-scale local impacts may have played a crucial role in the impact history of the Chang'E-5 landing site.

Effect of cooling rate during solidification on structure and mechanical properties of Cu45Zr48Al7 glass-forming alloy

The CuZr-based bulk metallic glass matrix composites have attracted great attention in recent years owing to their unique mechanical properties compared to bulk glassy samples. The vital effect of B2 CuZr phase on mechanical properties was previously confirmed in CuZr-based alloys with equiatomic concentrations of copper and zirconium. In this paper, the structures and mechanical properties of the Cu45Zr48Al7 alloy, which has hypereutectoid composition with respect to stoichiometric B2 CuZr phase, were studied. This alloy exhibits high glass-forming ability, but low tendency to form the B2 CuZr phase during solidification. However, we demonstrated that depending on the cooling rate during solidification, governed by sample diameter, either bulk metallic glass or bulk metallic glass matrix composite can be produced. In order to allow partial crystallization of the B2 phase during solidification with the volume fraction allowing to observe the strain hardening effect, the minimum cooling rate should be lower than 40 K/s. The composite consisting of a glassy outer layer and a crystalline core composed of the B2 phase exhibits fracture strength of the same level as the bulk glassy sample (above 1800 MPa) obvious work-hardening with a plastic deformation of about 6%.

Prediction of glass-forming ability based on multi-model fusion

At present, it is difficult to find metals with good glass-forming ability (GFA), seriously hindering the industrial application of metallic glasses (MGs). Therefore, it is urgent to develop a regression model that provides a prompt prediction for the critical diameter (Dmax) of alloys. Most established models rely heavily on elaborate feature descriptors and single algorithms, which may limit the predictive accuracy. In this work, the Stacking fusion is adopted to construct a more efficient model (Stack-Dmax). To avoid domain knowledge involved in feature engineering, only the alloy composition is treated as the input. Experiments revealed that compared to 6 individual models, the Stack-Dmax model is more robust and accurate regarding performance; it achieves improvement up to 41.61 %, 54.76 % and 35.67 % respectively in RMSE, R2 and MAE. The Stack-Dmax model is also better than the five most recently reported models based on RF, XGB, and CNN. In practical applications, our model exhibits potential for designing new La- and Mg-based MGs. These findings suggest that the Stacking approach provides an effective GFA-prediction model only based on the composition of alloys.

INFLUENCE OF B2O3 ON THE INTERACTION IN THE SiO–GeO2 SYSTEM

The influence of the B2O3 additive on the nature of the interaction in the SiO–GeO2 system was investigated by X-ray diffraction and IR transmission spectroscopy. The nature of the diffractograms of the SiO–GeO2–B2O3 system with a composition of 1:1:0.5 and 1:1:1 corresponds to the presence of SiO2 phases of hexagonal modification (quartz) and GeO2 of various modifications, as well as, possibly, a crystalline B2O3 phase. The exact value of the content of the reaction products and initial components could not be determined due to the significant content of the X-ray amorphous component of unknown composition. The broadening of the diffraction peaks and the presence of a distinct halo testify to the benefit of the processes of nanostructuring and glass formation. However, the absence of elemental germanium in the SiO–GeO2–B2O3 system, in contrast to the SiO–GeO2 system, was clearly established. The nature of the IR transmission spectra of samples with different content of B2O3 additive differ significantly from each other. Thus, the IR transmission spectra of the sample with a composition of 1:1:0.5 contain weak absorption bands due to the oscillations of the B–O bonds; instead, they reveal periodic oscillations characteristic of nanostructured systems. In the spectra of the sample with a composition of 1:1:1, the absorption bands due to the oscillations of the B–O bonds are very distinct, but there are no oscillations. Therefore, the addition of B2O3 probably accelerates the formation of Germanium monoxide, which in turn reacts with the B2O3 additive and possibly with SiO2 as one of the reaction products. Testing of samples of the SiO–GeO2–B2O3 system by the method of thermal evaporation in a vacuum revealed the advantages of the sample with a composition of 1:1:1 in the ability to form a strong and durable coating. It was possible to determine the refractive index for it, which is 1.93 at a wavelength of 1000 nm. Instead, the coating obtained from the 1:1:0.5 composition sample turned out to be unstable. A conclusion was made about the need for further optimization of the composition and synthesis conditions to obtain materials with the required parameters.

Ensemble learning based on stacking and blending predicts glass forming ability

Amorphous alloys have great commercial value due to their superior properties, but the glass forming ability (GFA) of most alloys is weak, which restricts their production and application, so it is important to predict GFA for saving the high cost of manufacture and experiment. In this paper, a new idea of fusing strong heterogeneous models to predict GFA is proposed, which 1532 experimental data are collected from published literature, and the critical casting diameter Dmax is predicted by glass transition temperature Tg, crystallization transition temperature Tx, and melting end temperature Tl using stacking-based ensemble learning methods, where Dmax represents GFA of the alloy. The results show that the prediction accuracy of the model reaches 0.7115, and the mean square error (MSE) and mean absolute error (MAE) are 0.0100 and 0.0667. Since the dataset is very rare in large thickness data, on the basis of the stacking ensemble model, this paper proposes an ensemble learning method based on blending to improve the generalization ability of the model, and its prediction accuracy is improved to 0.9040, and the MSE and MAE are reduced to 0.0090 and 0.0437, respectively. Experimental results demonstrate the promising potential of the new method to predict GFA.

A study of crystallization kinetics, phase formation and magnetic properties of (FeCoNiMn0.25Al0.25)75Si13B12 high-entropy metallic glass

The crystallization kinetics, phase formation and magnetic properties of (FeCoNiMn0.25Al0.25)75Si13B12 high-entropy metallic glass are investigated by thermal analysis, electron microscopic imaging, X-ray and magnetic tests. The results indicate that the alloy combines good glass forming ability and thermal stability. After heat treatment, the alloy precipitates with a feature of three-dimensional growth, while the α-Fe,Co phase first precipitates, and following the lamellar eutectic precipitate as Fe-B and Co2Si. This ultra-fine α-Fe,Co at low temperatures and the solid solution of non-ferromagnetic elements in the α-Fe,Co at high temperatures decrease the saturation magnetization of the alloy. In addition, the change from antiferromagnetic to ferromagnetic of Mn is confirmed through first-principles density functional theory calculations.

Fabrication of granular foam glass aggregates from soda lime silicate glass waste

Granular foam glass aggregates were fabricated from a soda lime silicate glass waste which utilized crude glycerol as a foaming agent and sodium silicate as a binder. The granulation and the foaming process were carried out by a granulator and an electric rotary furnace. The study investigated at first the foaming behavior of different foam glass formulations at various sintering temperatures. Three compositions were formulated which utilized glass powder at 85 wt%, 90 wt%, and 95 wt%, respectively. Sintering was carried out at temperatures from 800℃ to 1200℃ to evaluate for the foaming and melting characteristics. Foam glass with 90% glass powder showed overall uniform pore size distribution and small pores at 800℃ to 900℃ while heating above 1000℃ resulted in sample distortion caused by glass melting and the collapse of foam glass structure. Foam glass composition with 90% glass powder was selected for the fabrication of foam glass granules at the sintering temperatures of 850℃ and 900℃ in rotary furnace. The best result was obtained at 850℃ where the granules did not melt and stick together whereas at 900℃ glass melting on the surface of the foam glass granules occurred significantly.

Effects of Chest Physiotherapy and Effective Cough Exercise on Sputum Clearance and Respiratory Frequency in Tuberculosis Patients

Background: Tuberculosis (TB) is an infectious disease caused by Mycobacterium tuberculosis. Chest physiotherapy and cough exercises are one of the commonly used methods as part of TB treatment. This study aimed to determine the effects of chest physiotherapy and cough exercises on sputum clearance and respiratory frequency in TB patients. Subjects and Method: This was a quasy experiment study with no control group. The study was conducted at Dungus Respiratory Hospital, Madiun, East Java. A sample of 26 TB patients was selected purposively. The independent variables in the study were effective cough and chest physiotherapy. The dependent variable in this study was sputum discharge. Chest and cough physiotherapy interventions are effective in patients 3 times. This study used a measuring instrument in the form of a sputum glass. The data collected were analyzed quantitatively using the Mann-Whitney test to determine the effect of chest physiotherapy and effective cough exercises on pulmonary tuberculosis conditions. Results: After combination interventions of chest physiotherapy and effective cough exercises, sputum released (Mean= 29.35; SD= 0.85) was higher than before (Mean= 23.65; SD= 0.68). Respiratory frequency after intervention (Mean= 25.88; SD= 0.73) was higher than before (Mean= 27.12; SD= 0.98). Conclusion: Sputum secretion and respiratory frequency are higher than before chest physiotherapy and cough exercises in TB patients. Keywords: chest physiotherapy, cough exercise, physiotherapy, tuberculosis. Correspondence:Nurul Fithriati Haristah. Study Program of Physiotherapy, Health Polytechnics, Ministry of Health Surakarta. Email: nurulfithriati_haritsa@yahoo.com. Mobile: +6285157577816.

Nanomechanical properties of Al-Tb marginal metallic glass

Al-Rare Earth (RE) metallic glasses provide an effective model system to study the effect of nanocrystallites in an amorphous matrix on nanomechanical behavior. In this work, we achieved a series of Al-Tb metallic glass-crystalline composites with systematically varying crystalline content through annealing. The nanomechanical properties were characterized using micropillar compression tests and nanoindentation for as-quenched amorphous and annealed amorphous/nanocrystalline composite specimens. The promising hardness increases after annealing from 3.0 GPa to 4.6 GPa and elastic modulus increment from 68 GPa to 92 GPa were discussed in detail, considering the structural features of Al-RE marginal metallic glass formers. The increase in elastic modulus is associated with the nucleated fcc-Al nanocrystals that divide the amorphous matrix, leading to the branching of the shear bands. The correlation between the fcc-Al nanocrystals and the behavior of shear bands was discussed in detail.

Turing pattern and chemical medium-range order of metallic glasses

The formation of bulk metallic glass requires the constituent elements to have a negative heat of mixing but has no restrictions on its magnitude. An understanding of this issue is lacking due to the absence of a valid method for describing chemical ordering of metallic glasses. For example, the radial distribution function is ineffective in identifying the elemental preferences of packed atoms. Here, we show that using molecular-dynamics simulation, the chemical medium-range ordering of liquid alloys can be evaluated from persistent homology. This inherently arising chemical medium-range order in metallic glasses is exclusively regulated by the activation and inhibition of the constituent components, making the topology of metallic glasses a Turing pattern. The connecting schemes of atoms of the same species form three distinct regions, reflecting different correlations at the short and medium length scales, while the difference in the schemes corresponds to chemical ordering. By changing the elemental types, it is demonstrated that the chemical medium-range order strongly depends on the relative depth of the interatomic-potential wells. The study separates metallic glasses from crystals under the condition of negative heat of mixing by emphasizing their fundamental difference in interatomic potentials.

NiTi2, a New Liquid Glass.

Many endothermic liquid-liquid transitions, occurring at a temperature Tn+ above the melting temperature Tm, are related to previous exothermic transitions, occurring at a temperature Tx after glass formation below Tg, with or without attached crystallization and predicted by the nonclassical homogenous nucleation equation. A new thermodynamic phase composed of broken bonds (configurons), driven by percolation thresholds, varying from ~0.145 to Δε, is formed at Tx, with a constant enthalpy up to Tn+. The liquid fraction Δε is a liquid glass up to Tn+. The solid phase contains glass and crystals. Molecular dynamics simulations are used to induce, in NiTi2, a reversible first-order transition by varying the temperature between 300 and 1000 K under a pressure of 1000 GPa. Cooling to 300 K, without applied pressure, shows the liquid glass presence with Δε = 0.22335 as memory effect and Tn+ = 2120 K for Tm = 1257 K.

Microstructure and mechanical properties of an experimental lithium disilicate dental glass-ceramic

After testing over 50 experimental lithium disilicate (LS2)-based glass-ceramic (GC) compositions and evaluating their glass-forming ability and the effect of various heat treatments on their crystallized fraction, crystal size, and morphology, a particularly promising formulation was selected for the optimization of the mechanical properties of materials. The specimens were divided into groups submitted to a nucleation heat treatment at different times and temperatures, i.e., T1 (500 °C/90′), T2 (500 °C/180′), T3 (500 °C/360′) and T4 (480 °C/360′), followed by a crystal growth treatment to induce the lithium metasilicate (700 °C) and LS2 (840 °C) phases. However, a third (minor) phase, lithium phosphate, also precipitated. IPS e.max CAD was used as the control group (C, 500 °C/360′). The elastic modulus (E) was measured by the impulse excitation technique (ASTM E 1876-15), while the Vickers hardness (HV) and biaxial flexural strength (BFS) were determined by indentation and the piston-on-three balls test (ISO 6872), respectively. The E and HV results were analyzed by ANOVA one-way with Games–Howell post-hoc test, whereas the BFS data were investigated by Kruskal-Wallis with Dunn's post-hoc test (α = 0.05). The E of all GCs were within the expected range for commercial LS2 glass-ceramics. The T2 and T4 GCs exhibited the best properties when compared to the C group, and despite their relatively small crystallized fraction (∼57 %), they showed a hardness of 5.8 ± 0.2 GPa, a value that is adequate and statistically equal to that of the control group. The same groups reached BFS values of 359 ± 89 MPa and 493 ± 147 MPa, respectively, which are also statistically equal to that of the C group (338 ± 61 MPa). The mechanical properties of the material studied was successfully optimized through variations in the nucleation temperature and time, reaching values comparable to (but not better than) commercial dental glass-ceramics.

Chemical Bonding Origin of Mechanically Induced Glass Formation in a Coordination Polymer

Chemical Bonding Origin of Mechanically Induced Glass Formation in a Coordination Polymer

Role of Cr Element in Highly Dense Passivation of Fe-Based Amorphous Alloy.

The effect of the Cr element on the corrosion behavior of as-spun Fe72-xCrxB19.2Si4.8Nb4 ribbons with x = 0, 7.2, 21.6, and 36 in 3.5% NaCl solution were investigated in this work. The results show that the glass formability of the alloys can be increased as Cr content (cCr) is added up to 21.6 at.%. When cCr reaches 36 at.%, some nanocrystals appear in the as-spun ribbon. With increasing cCr content, the corrosion resistances of as-spun Fe-based ribbons are continually improved as well as their hardness properties; during the polarization test, their passive film shows an increase first and then a decrease, with the highest pitting potential as cCr = 7.2 at.%, which is confirmed by an XPS test. The dense passivation film, composed of Cr2O3 and [CrOx(OH)3-2x, nH2O], can reduce the number of corrosion pits on the sample surface due to chloride corrosion and possibly be deteriorated by the overdosed CrFeB phase. This work can help us to design and prepare the highly corrosion-resistant Fe-based alloys.