Amorphous Research Articles

Fluctuation Phenomena in Single Injection Solid State Spherical Devices under Amorphous Regime

Fluctuation effects in single injection solid-state sphere devices working in the amorphous regime are an interesting area of study that has effects on the stability and performance of electronic devices. This study looks into how changes in these devices' working features affect them, focused on how they act when they are in a fluid state. Solid-state sphere devices have unique electrical and structure properties. These properties are more noticeable in amorphous materials, where the disorder of the atoms affects how charges move and how reliable the device is. We look at the fluctuation effects that happen during single injection processes, in which carriers are brought into the device from a single source. It is called an amorphous phase because there is no long-range order. The inserted charge carriers and the disordered atomic lattice respond in a complicated way. The device's efficiency measures, like charge build up, current-voltage traits, and noise levels, change a lot because of this interaction. In order to describe these changes, our research uses both practical and theoretical methods. We use advanced measurement methods to find out about electrical reactions and noise bands, and we're also making theoretical models to figure out how the things we see happen. The results show that changes are affected by things like carrier trapping, limited states, and dynamic disorder in the amorphous material. The results of this study help us learn more about how stable and reliable single-injection solid-state sphere devices are in amorphous environments. These results could help improve the performance of amorphous materials used in many electronic and optical systems by making device designs more efficient.

Beyond the Surface: Interconnection of Viscosity, Crystal Growth, and Diffusion in Ge25Se75 Glass-Former.

The knowledge of viscosity behavior, crystal growth phenomenon, and diffusion is important in producing, processing, and practical applications of amorphous solids prepared in different forms (bulk glasses and thin films). This work uses microscopy to study volume crystal growth in Ge25Se75 bulk glasses and thermally evaporated thin films. The collected growth data measured over a wide temperature range show a significant increase in crystal growth rates in thin films. The crystal growth is analyzed using near-surface viscosities obtained in bulks and thin films using nanoindentation and melt viscosities measured by a pressure-assisted melt filling technique. The crystal growth analysis provides information on the size of the structural units incorporated into the growing crystals, essential for estimating the diffusion coefficients and explaining the difference in crystal growth rates in bulk and thin films. The crystal growth analysis also reveals the decoupling between diffusion and viscous flow described by the Stokes-Einstein-Eyring relation. Moreover, to the authors' best knowledge, the manuscript provides the first evaluation estimation of the effective self-diffusion coefficient directly from growth data in chalcogenide glass-formers. The present data show a similar relation between diffusion coefficients (D) and crystal growth rates (u): u ≈ D0.87, which is found in several molecular glasses.

Formulation and Evaluation of Nano Suspension Based Oro Disoersible Film of Aripiprazole

The present study was aimed to enhance the solubility and dissolution of BCS class 4 drug aripiprazole, by nano formulation approach. Acid-base neutralization method had been used to produced nanosuspension. The nanosuspensions remained stable without any aggregations with particle size 209.6nm and PDI 0.247. Zeta potential was found to be 3.5mV. Drug content, Entrapment and solubility of nanosuspension formulations were determined. In vitro drug release of the selected formulation has shown a drug release of 95.63% by the end of 1 hr, whereas plain drug suspension has shown only 12.3% release. XRD and DSC studies revealed that the solid form of aripiprazole altered from the crystalline state to the amorphous state after incorporation into nanosuspensions. Hence, from the results, it can be concluded that Aripiprazole, when formulated by acid-base neutralization method as a nanosuspension, leads to enhanced solubility, dissolution, and stability

Er3+/Tm3+ codoped CaF2 based oxyfluoroborosilicate glass-ceramics for fiber laser applications

Transparent Er3+/Tm3+ codoped CaF2 based oxyfluoroborosilicate glass-ceramics (BSEr1TmxGCs) with variable Tm3+ concentration were prepared through melt quench process followed by reheat treatment at 450 °C/1h. They were characterized through differential scanning calorimetry (DSC), powder X-ray diffraction (XRD), Fourier transform infrared (FTIR) Raman spectroscopy, near infrared (NIR) emission and luminescence decay. The formation of CaF2 nanocrystallites against oxyfluoroborosilicate glassy phase was confirmed by scanning electron microscopic (SEM) and hi-resolution transmission electron microscopic (HRTEM) studies. The NIR emission properties were investigated at 460 nm diode laser pumping. The applicability of BSEr1TmxGCs were examined by evaluating effective bandwidth (Δλeff), stimulated emission cross-section (σe), gain bandwidth (σe × Δλeff), figure of merit (σe × τR) and quantum efficiency (ηQE). The energy transfer efficiency (ηET), rate of energy transfer (WET) between Er3+ and Tm3+ and the rate of non-radiative transitions (WNR) were also calculated. The comparative NIR emission performance suggests that the BSEr1Tm1GC has proficiency for 1530 nm broadband fiber lasers and optical amplifiers in short wavelength and conventional wavelength (S + C) band communication window.

Design and development of large-diameter Mg-Zn-Ca bulk metallic glass for biomedical applications: A mechanical and corrosion perspective

Being amorphous, bulk metallic glasses (BMGs) exhibit superior properties compared to their crystalline alloy counterparts. Amorphous materials are preferred for their excellent mechanical and degradation behavior. Among the various elemental combinations, MgZnCa has shown the most promising results, as evidenced by the literature. However, the maximum achievable size of the metallic glasses remains a bottleneck. The current work aims to address this challenge and achieve it splendidly with a systematic methodology by developing larger diameter MgZnCa BMGs through vacuum induction casting using a specially designed copper mold. The optimal composition was formalized for glass formation of the Mg65Zn31Ca4 system using the CALPHAD technique. As a result, a 6.5 mm diameter glassy alloy was successfully obtained. The XRD and TEM analysis experiments demonstrated a perfect amorphous structure of the developed sample. The anti-corrosion properties of the as-cast glass increased, followed by enhancement in the yield strength and hardness in contrast to the properties of the human bone. Furthermore, the surface wettability analysis showed an adequate surface obtained to promote fibroblast adhesion. In conclusion, the current work represents a notable progress in the fabrication of larger-diameter MgZnCa BMG for biomedical applications, considering that the biggest diameter ever reported in the MgZnCa system was more than a decade ago.

Acoustic resonance technology and quality by design approach facilitate the development of the robust tetrandrine nano-delivery system

The aim of this study was to develop a sufficiently robust tetrandrine (Tet) nano-delivery system using acoustic resonance (AR) technology and freeze-drying technology. This system can effectively improve the solubility and dissolution properties of Tet, along with high stability and scale-up adaptability. Firstly, 54 stabilizers were screened simultaneously in a high-throughput manner with the help of AR technology to fully explore the optimal prescription space of tetrandrine nanosuspension (Tet-NS). The Plackett-Burman design was used to screen for critical variables severely affecting the quality of Tet-NS. The Box-Behnken design was used to investigate and optimize critical variables to obtain optimal nanosuspensions. The optimal prescription was successfully scaled up by 100 times, which was the initial exploration of its commercial scale production. Solidification studies have shown that formulations with 2.44% fructose as the cryoprotectant have excellent redispersibility. Compared with pure Tet, Tet in Tet-NS showed a significant increase in solubility and dissolution rate in water. Fourier transform infrared (FT-IR) demonstrated that no significant interactions occurred between the drug and excipients in Tet-NS. Powder x-ray diffraction analysis (PXRD) indicated that some of the Tet transformed into amorphous state during the preparation process. In short-term stability study, Tet-NS successfully maintained its physical stability. In summary, under the guidance of the QbD concept, this study rapidly developed Tet-NS using acoustic resonance technology, which can effectively improve the solubility and dissolution properties of Tet. During the development of Tet-NS, AR technology has demonstrated high particle size reduction capability, the ability to process multiple sets of formulations in parallel, and excellent scale-up capability. Meanwhile, the method and concept of this study are not limited to Tet, but also applicable to other poorly water-soluble drugs.

Impact of amorphous structure on CO2 electrocatalysis with Cu: A combined machine learning forcefield and DFT modelling approach

Amorphous materials hold significant promise for enhancing electrocatalytic CO2 reduction (CO2R) performance, but their intricate structures present challenges in understanding their behaviour. We present a computational investigation combining machine learning force fields and DFT calculations to explore amorphous copper (Cu) as a potential catalyst for the CO2R to C1 and C2 products. Our study reveals that amorphous Cu surfaces, compared to crystalline counterparts, offer a wider range of coordination sites, leading to a multitude of active centres for CO2 adsorption. Notably, some investigated surfaces spontaneously activate CO2, demonstrating their potential for efficient conversion. Furthermore, the intermediates of the CO2R on these surfaces exhibit enhanced stability, translating to lower overpotentials and improved selectivity. This work paves the way for further research and development in using amorphous Cu-based catalysts for sustainable CO2 conversion technologies, offering significant potential for mitigating climate change.

Amorphous Nanobelts for Efficient Electrocatalytic Ammonia Production.

One-dimensional (1D) amorphous nanomaterials combine the advantages of high active site concentration of amorphous structure, high specific surface area and efficient charge transfer of 1D materials, so they present promising opportunities for catalysis. However, how to achievie the balance between the high orientation of 1D morphology and the isotropy of amorphous structure is a significant challenge, which severely obstructs the controllable preparation of 1D amorphous materials. Guided by the hard-soft acids-bases theory, here we develop a general strategy for preparing 1D amorphous nanomaterials through the precise modulation of bond strength between metal ions and organic ligands for a moderated fastness. The soft base dodecanethiol (DT) is multifunctionally served as both structure-regulating agent and morphology-directing agent. Compared with the borderline acids (e.g. Fe2+, Co2+, Ni2+) to construct amorphous structure, soft acid of Cu+ which produced crystalline nanobelts can still be amorphized by reducing the hardness of Cu ions through redox reaction to weak Cu-SR bond. Due to the combined advantages of amorphous structure and one-dimensional morphology, amorphous CuDT nanobelts exhibited excellent electrocatalytic activity in electrochemical nitrate reduction, outperformed most of the reported Cu-based catalysts. This work will effectively bridge the gap between traditional 1D crystalline nanomaterials synthesis and their amorphization preparation.

Highly Efficient Manganese Bromides with Reversible Luminescence Switching through Amorphous-Crystalline Transition.

While luminescent stimuli-responsive materials (LSRMs) have become one of the most sought-after materials owing to their potential in optoelectronic applications, the use of earth-scarce lanthanides remains a crucial problem to be solved for further development. In this work, two manganese-based LSRMs, (R)-(+)-1-phenylethylammonium manganese bromide, (R-PEA)2MnBr4, and (S)-(-)-1-phenylethylammonium manganese bromide, (S-PEA)2MnBr4, are successfully demonstrated. Both (R-PEA)2MnBr4 and (S-PEA)2MnBr4 show a kinetically stable red-emissive amorphous state and a thermodynamically stable green-emissive crystalline state at room temperature, where the fully reversible transition can be done through melt-quenching and annealing processes. Based on this property, a reusable manganese-halide-based time-temperature indicator is demonstrated for the first time. Furthermore, an X-ray scintillator with a low limit of detection (18.1 nGy/s) and a high spatial resolution limit (30.0 lp/mm) are achieved by exploiting the high transparency of amorphous states. These results uncover the multifunctionality of manganese halides and pave the way for upcoming research.

Electrochemical grafting of diazonium salts on silica-terminated versus H-terminated silicon

Diazonium salts are one of the most widely used molecules for functionalising electrode surfaces, due to their high reactivity toward a range of different electrodes but have mostly been studied on carbon and gold. Recent work has demonstrated that diazonium salts can be reduced on silica-terminated silicon (Si/SiOx) despite silica (SiOx) being an electrically insulating material, but this interesting phenomenon was only demonstrated on one specific crystal orientation, Si(111) using specific diazonium salts molecules – a more complete understanding of the electrochemical properties of these silica-terminated silicon electrodes remains unclear. In this work, we develop a thorough understanding of the reduction of diazonium compounds on silica-terminated silicon using silicon with different crystal orientation and using nano-structured silicon surfaces that are chemically etched to simultaneously expose different crystal orientations. A comparison between the reduction process on oxide free silicon (Si–H) and silica-terminated Si is then made to reveal the effect of the crystal orientation (amorphous vs crystalline) and the insulating nature of the distal surface (Si‒H vs SiOx) on the reduction process. Results show that diazonium salts form, well-packed thin films on silica-terminated silicon regardless of the crystal orientation of the silicon. The rate of diazonium reduction was found to be sensitive to the crystal orientation of Si only when the diazonium salts are in direct contact with the crystal plane (i.e. in contact with Si–H) as opposed to when there is a thin layer of native amorphous oxide material in between. The reduction rate is sufficiently slow on silica-terminated silicon that at slow scan rates, the system reaches a steady state current and become diffusion controlled. This is not observed on oxide-free silicon electrodes which are observed to be governed by a kinetically driven mechanism. These findings deepen our understanding of the electrochemical activity of silica-terminated silicon surfaces which are widely used in solar cells, electronics, chemical and biosensors.

Fe-based metallic glass coatings with suppressed cracks and enhanced wear resistance prepared by extreme high-speed laser cladding

Fe-based metallic glass (MG) coatings draw great attentions due to their excellent wear resistance. The recently developed extreme high-speed laser cladding (EHLC) provides a promising method for their fabrication but limited by the strong tendency to crack. Besides that, the deep insight into the structure evolution and the failure mechanism of the coating is still lacked. Thus, the understanding of the crack origin and the prevention of crack are of great importance. In the present work, Fe-Mo-Cr-Y-C-B MG coatings with adjustable glassy phase content were successfully fabricated by EHLC. The microstructure characterization of the coatings reveals that the cracks is main caused by the hard and brittle nanocrystalline phases precipitations of monoclinic Mo12Fe22C10 and (Fe, Cr)23C6 carbides in the heat affected zone. Therefore, the cracking of the coatings can be effectively reduced by increasing the glassy phase content. Subsequently, the hardness distribution, wear performance and wear mechanism of the coatings were investigated. The results showed that increasing the glassy phase content can effectively achieve low wear rate. The prepared Fe-Mo-Cr-Y-C-B MG coatings exhibit abrasion loss as low as 3.54·10−6 mm3 (N m)−1, which is an order of magnitude lower than that of the 45# steel substrate. The wear of the coatings is primarily attributed to the fatigue wear accompanied with slighting oxidative wear. By suppressing the brittle precipitated crystalline phases in the coating, the fatigue wear can be reduced and the wear resistance of the coatings can be improved. The present work provides insights into the crack prevention and were performance improvement of the Fe-based MG coatings prepared by EHLC.

Mechanistic Insights into the Evolution of Graphitic Carbon from Sulfur Containing Polar Aromatic Feedstock.

In the realm of carbon fiber research, a variety of structural configurations is noted, comprising crystalline, noncrystalline, and semicrystalline forms. Recent investigations into this domain have revealed an array of intriguing phases of carbon, among which amorphous graphite is the most notable for its unique mechanical, thermal, and electrical properties that arise from its inherent topological disorders. In this study, we utilized the ReaxFF molecular dynamics (MD) simulations to investigate the carbonization and graphitization processes involved in the production of amorphous graphite from benzothiophene, a sulfur-containing polar aromatic precursor. We developed C/H/S ReaxFF force field parameters to describe the high-temperature chemistry of benzothiophene. Our investigation reveals the reaction mechanisms, providing critical insights into the underlying chemical processes toward the formation of amorphous graphite and the structural characteristics of the end products. The formation of volatile gaseous molecules and their continuous elimination led to the development of noncontinuous layered graphite structures analogous to amorphous graphite consisting of pentagons, hexagons, and heptagons. These findings offer unprecedented insights into the carbonization and graphitization processes of sulfur-containing heavy-end aromatic feedstock. This knowledge lays the groundwork for advancing synthesis methods and developing amorphous graphite materials with specific properties.

Enhancing Fire Resistance of Geopolymers Modified with Thermal Insulation Additives

This study aims to improve the fire resistance of geopolymers by adding thermal insulation materials. These additives help the material perform better at high temperatures. Previous research focused on using fly ash, metakaolin, and zeolite in geopolymer composites. This study looks at how porous additives affect compressive strength and whether non-destructive testing can measure damage after heat exposure. Four temperature tests were set: 400 °C for 60 min, 400 °C for 120 min, 800 °C for 60 min, and a maximum of 658 °C for 120 min. The results showed that the compressive strength and ultrasonic pulse velocity (UPV) dropped as the temperature increased, with a sharp decrease at 800 °C. Unmodified samples broke apart at high temperatures, while modified samples lost 40% to 70% of their strength. The study confirmed that a dense, amorphous matrix improves heat resistance, even with porous additives like fly ash. A link between UPV and compressive strength was found, suggesting non-destructive testing could be useful for checking structural integrity after a fire.

The Solid-State Multi-Color Fluorescence Switching from a [2.2]Paracyclophane-Based Triarylborane.

The fluorophores, the fluorescence of which can be switched between multi bright colors in the solid state, show promising applications not only in the sophisticated multicolor display but also in the advanced encryption and anti-counterfeiting systems. However, it is very challenging to obtain such fluorophores. Herein, we disclose such an example, g-BPhANMe2-Cp, which contains an electron-donating dimethylamino (NMe2) and an electron-accepting [(2-dimesitylboryl)phenyl]acetyl at the pseudo-gem position of [2.2]paracyclophane skeleton. This molecule can display tricolor mechanochromic luminescence (MCL) due to the different responses of the mechanically ground amorphous state to heating and solvent-fuming. Owing to the absence of intermolecular π-π interactions in the solid state, the fluorescence efficiency is very high irrespective of its morphological state (ΦF=0.60-0.87). Moreover, this molecule also displays reversible acidochromic luminescence (ACL) by protonation and deprotonation of NMe2 with trifluoroacetic acid (TFA) and triethylamine (TEA), respectively. The protonated sample fluoresces (ΦF=0.31) at much shorter wavelength due to the interruption of intramolecular charge transfer process. Therefore, with the combination of tricolor MCL and ACL properties, the solid-state emission of g-BPhANMe2-Cp can be switched among four bright fluorescence colors of yellow, green, cyan and blue via treatment with appropriate stimulus.

Modular Combinatorial Development of Crystal‐Glass Nano‐Heterostructured Copper Alloys with Ultrahigh Strength and Large Deformability

AbstractOvercoming the strength‐ductility trade‐off in metals and alloys entails the optimization of the compositions and dedicated microstructural design, which remains experimentally laborious and challenging. Here, a combinatorial method is devised to construct a Cu‐Ti alloy library encompassing diverse compositions, microstructures, and mechanical properties, allowing to efficiently identify a copper alloy with an unprecedented yield strength of 3.8 GPa and high deformability. The exceptional properties are attributed to a crystal‐glass nano‐heterostructure (CGNH) consisting of nanograins, nano twins, and glassy phases. Ultrahigh strength stems from the extreme strengthening of structural‐unit refinement and the avoidance of softening caused by grain‐boundary sliding through the inclusion of glassy phases between nanograins. Remarkable deformability is associated with the activation of homogeneous flow in nanosized glassy phases, complemented by coordinated nanocrystal rotation. The CGNH architecture offers a potent route to overcome the trade‐off between alloy strength and deformability.

Insights into glass surface dynamics from fast scanning calorimetry studies of softening and vaporization of ultrathin molecular films.

Chemical and physical processes on the surfaces of amorphous solids have been the focus of many studies over the past decades. These studies have established that dynamics in a thin layer near a glass surface are often dramatically faster than those in the glass bulk. Nevertheless, recent advances also emphasize the need for new experimental techniques capable of characterizing the structure and dynamics of the near-surface regions in glassy materials at the molecular length scale. Using a quasi-adiabatic fast scanning calorimetry (FSC) technique, we have investigated softening and vaporization of pure amorphous methylbenzene films of moderately heightened kinetic stability with thicknesses ranging from 1 to 20nm. The analysis of the FSC thermograms reveals the existence of a high fictive temperature (liquid-like) layer on the surface of the solid glass with a thickness of 3.5 ± 0.5nm or seven molecular diameters. Furthermore, the width of the boundary between liquid-like and solid layers in the films is less than 1nm. These preliminary findings compliment and substantiate past determinations of the mobile surface layer thicknesses obtained by introduction of nanoparticles or spectroscopic molecular probes to near-surface regions of amorphous samples. The developed FSC methodology will advance the theoretical and computational research by providing calorimetric data on the enhanced interfacial dynamics phenomenon in a variety of low-molecular-weight amorphous materials.

Flexoelectricity in amorphous hafnium oxide (HfO2)

Flexoelectricity, inherent in all materials, offers a promising alternative to piezoelectricity for nanoscale actuation and sensing. However, its widespread application faces significant challenges: differentiating flexoelectric effects from those of piezoelectricity and other phenomena, verifying its universality across all material structures and thicknesses, and establishing a comprehensive database of flexoelectric coefficients across different materials. This work introduces a groundbreaking methodology that accurately isolates flexoelectricity from piezoelectric, electrostrictive, and electrostatic effects, with a detection threshold extending below 1 fC/m. The robustness of this method is demonstrated through its application to amorphous hafnium oxide, successfully measuring a flexoelectric coefficient of 105 ± 10 pC/m. This measurement signifies the first measurement of flexoelectricity in hafnia, as well as in any amorphous material. In addition, the study compiles a list of published flexoelectric coefficients, revealing an important insight. The relationship between the flexoelectric coefficient and the material’s relative permittivity is better approximated by a quadratic proportionality. This challenges the traditional linear assumption proposed in Kogan’s work and opens new avenues for future research in flexoelectric materials.

Fabrication, Physical, Structural, Optical Properties, and γ‐Ray Attenuation Attributes of Germanate Borosilicate Glasses: Role of GeO2

AbstractSamples of germanium borosilicate glasses with chemical formula 50.5B2O3 + 0.5CeO2 + 10SiO2 + (20‐x) CaO + 19Na2O + XGeO2 with 0 (GeO0) ≤ X ≤ 5 (GeO5) mol% were fabricated by using the melt quenching technique. Structure, physical, and optical properties as well as radiation attenuation capacity was examined. XRD data confirmed that GeOX samples were in amorphous state. The density (ρ) of the prepared glass samples increased from 2.24 to 2.55 g/cm3, while the molar volume (Vm) slightly declined from 26.8 to 26.42 cm3/mol. The UV absorption edge shifted to a higher wavelength as the concentration of GeO2 increased. The values of direct band gap ranged from 3.36 to 2.91 eV, and the indirect ranged from 3.12 to 2.75 eV. Urbach energy (Eu) values fluctuated between 0.65 to 0.16 eV. As the Ge4+ ion increased, the glass sample's refractive index enhanced. Mass attenuation coefficients (MACs) of GeOX samples increased from 6.788 to 10.381 cm2/g at 0.015 MeV. The GeO5 sample possessed the lowest half value layer (HVL) and mean free path (MFP). Effective atomic number (Zeff) of GeOX possessed the same trend of MAC. Results confirmed that the suggested GeOX glasses can be applied in different optical and radiation attenuation applications.

Influence of the synthesis route on optical and luminescence properties of glass-ceramic doped with europium ions

The production of transparent glass-ceramic materials often faces challenges, such as inhomogeneities, inclusions, uncontrolled crystallization and other defects that make glass ceramics unsuitable for fiber optics, for example. At the same time, the chosen chemical composition is valuable for its unique properties. The present study investigated the effect of different methods of synthesizing glass-ceramic silica-germanium-antimony matrices on their transmittance optimization and luminescence properties where the conventional melt-quenching route is insufficient in terms of the transparency and homogeneity of the material obtained. The effect of heat treatment on the studied properties was also considered. Full Text: PDF References G.A. Khater, E.M. Safwat, J. Kang, Y. Yue, A.G.A. Khater, "Some Types of Glass-Ceramic Materials and their Applications", Int. J. Res. Stud. Sci. 7(3), 1 (2020). DirectLink J. Deubener, M. Allix, M.J. Davis, A. Duran, T. Höche, T. Honma, et al., "Updated definition of glass-ceramics", J. Non-Crystalline Solids 501, 3 (2018). CrossRef W. Blanc, Y. Gyu Choi, X. Zhang, M. Nalin, K.A. Richardson, G.C. Righini, et al., "The past, present and future of photonic glasses: A review in homage to the United Nations International Year of glass 2022", Progr. Mat. Sci. 134, 101084 (2023). CrossRef P. Golonko, M. Kochanowicz, P. Miluski, M. Kuwik, J. Pisarska, W. Pisarski, J. Dorosz, M. Leśniak, D. Dorosz, A. Basa, J. Żmojda, "Glass-ceramic optical fibers with controlled crystallization of core doped with europium ions", Ceram. Int. S0272884224002955 (2024). CrossRef J. Zmojda, M. Kochanowicz, P. Miluski, A. Baranowska, A. Basa, R. Jadach, M. Sitarz, D. Dorosz, "The influence of Ag content and annealing time on structural and optical properties of SGS antimony-germanate glass doped with Er3+ ions", J. Mol. Struct. 1160, 428 (2018). CrossRef X. Liu, J. Zhou, S. Zhou, Y. Yue, J. Qiu, "Transparent glass-ceramics functionalized by dispersed crystals", Progr. Mat. Sci. 97, 38 (2018). CrossRef T.N.L. Tran, A. Chiasera, A. Lukowiak, M. Ferrari, "Eu3+ as a Powerful Structural and Spectroscopic Tool for Glass Photonics", Materials 15, 1847 (2022). CrossRef Z. Li, L. Tan, C. Chen, D. Zhou, L.R. Jensen, J. Ren, Y. Zhang, J. Qiu, Y. Yue, "The effect of melt-homogenization and heat-treatment on the optical properties of the rare earth doped oxyfluoride glass-ceramics", J. Non-Cryst. Solids 593, 121773 (2022). CrossRef D. Dorosz, M. Kochanowicz, R. Valiente, A. Diego-Rucabado, F. Rodríguez, N. Siñeriz-Niembro, et al., "Pr3+-doped YPO4 nanocrystal embedded into an optical fiber", Sci Rep. 14, 7404 (2024). CrossRef

Synergistically ceramization of rubber system for fire safety cable by sepiolite functionalized with boron-based nanoparticles

In this research, a novel ethylene propylene diene monomer rubber (EPDM) formulation for cable with high ceramization efficiency was prepared by the addition of functionalized sepiolite with boron fluxing compound nanoparticles (SEPTB) obtained by precipitation route. Non-functionalized sepiolite (SEP) has been incorporated to the system for reference. EPDM materials were characterized by standardized tests measuring their behavior against fire and important improvements were observed, especially in terms of smoke production (25% reduction of the smoke production compared with the formulation using SEP) presenting a remarkable behaviour against dripping and self-extinction when a flame is directly applied. The mechanism of ceramization under fire conditions was discussed. It was found that EPDM system with SEPTB additive transformed into a rigid ceramic after treating at 1000°C. In this particular case, the ceramization was more efficient due to the sepiolite transformation to enstatite at lower temperatures (∼750 vs ∼850°C) combined with the “in situ” formation of a glassy phase which notably enhances the reinforcement of the char layer by forming a reinforcing 3D enstatite fibers net structure that reduces smoke production and even totally avoids the dripping of melted polymer by the action of the heat in a fire event. This work provides new insights for the preparation of high-performance synergist additive based on sepiolite for the enhancement of fire retardance of EPDM system for cable applications.