Amorphous Research Articles

Effect of sputtering power and substrate bias on microstructure, mechanical properties and corrosion behavior of CoCrFeMnNi high entropy alloy thin films deposited by magnetron sputtering method

The CoCrFeMnNi high entropy alloy thin films with crystalline (solid solution) structure or amorphous state were fabricated by magnetron sputtering process at different target powers and different substrate bias. Effects of the target power and substrate bias on the characteristics of the CoCrFeMnNi thin films such as microstructures, morphology and surface topography, as well as mechanical properties and corrosion behavior were studied. Phase prediction was calculated by using thermodynamic and kinetic criteria under various deposition conditions. The enthalpy, entropy, δ and Ω parameters, and electronegativity differences influenced the solid solution stability of thin films. These parameters led to the formation of solid solutions with crystalline or amorphous structures under specific limits, which corresponded to the practical XRD and TEM analysis results. Using a substrate bias in the deposition of CoCrFeMnNi thin film changed the amorphous structure to a crystalline (solid solution (BCC + FCC)) at higher target powers (200 and 300 W). On the other hand, the film structure was entirely amorphous at all sputtering target powers without the substrate bias. The mechanical properties, such as hardness, Young's modulus, film strength, and fracture toughness of CoCrFeMnNi thin film, can be enhanced by using the substrate bias and increasing the sputtering power. The potentiodynamic polarization test in 3.5 wt% NaCl aqueous solution indicated that the deposition of CoCrFeMnNi thin films at different sputtering powers and without substrate bias could increase the corrosion resistance of 304 stainless steel substrate. Using the substrate bias of −100 V in the fabrication of CoCrFeMnNi thin film decreased the corrosion current density and increased its polarization resistance.

Investigation the effect of surface treatment on the mechanical properties of coating

AbstractThe study analyzed surface treatment's impact on mechanical properties of Fe-based amorphous coatings. Specimens underwent six-hour treatments at 670 and 770 °C using vacuum heat. Results revealed distinct mechanical features in the coating: Vickers hardness reached 755, scanning electron microscope images displayed glassy phases, showcasing good wear resistance and compressive residual stresses at around −55 MPa. A remarkable 122% increase in compressive residual stress was noted through combined vacuum heat treatment and sandblasting. Volume wear decreased from the initial 18 to 14 mm3 after treatment at 670 °C followed by sandblasting, indicating a 30% enhancement in wear resistance. Yet, using vacuum heat treatment at 770 °C negatively impacted the coating's properties.

Effect of the volume fraction of nanocrystals on the mechanical properties of (Fe0·9Ni0.1)86B14 amorphous/nanocrystalline alloy

The effect of the volume fraction of nanocrystals on the macroscopic mechanical properties and microscopic atomic structure of Fe-based nanocrystalline alloys, as well as the relationship between the two, is an urgent issue to be explored. Seven nanocrystalline alloys with different volume fractions of nanocrystals were formed by annealing treatment of (Fe0·9Ni0.1)86B14 amorphous precursor. Through hardness, flat plate bending, and nanoindentation experiments, it is found that when the volume fraction of nanocrystals reaches the range of 45–55 %, there is an abrupt change in the macroscopic mechanical properties. Specifically, when the volume fraction is less than this range, the properties inherit the amorphous matrix, however, larger than this range, the properties are dominated by precipitated nanocrystalline phases. Meanwhile, based on the molecular dynamics simulation method, seven Fe90Ni10 amorphous nanocrystalline models with different volume fractions of body-centered cubic nanocrystals are established, and the deformation mechanism of models and the evolution of their microstructures during the nanoindentation process are obtained intuitively. Moreover, it is further revealed that the significant changes in the Voronoi polyhedral index, which represents the microscopic atomic structure in this range of nanocrystal volume fractions, are the main reason for the abrupt changes in the mechanical properties at the macroscopic level.

Thermal decomposition and shock response mechanism of crystalline and amorphous 2,4-dinitroanisole (DNAN) by ReaxFF/lg reactive molecular dynamics simulations

DNAN (2,4-dinitroanisole) is a popular melt-cast carrier explosive in the field of insensitive ammunition. The decomposition mechanisms of crystalline and amorphous DNAN were explored in this work through ReaxFF-lg molecular dynamic simulations under constant temperature (2000 K, 2500 K and 3000 K), programmed heating (10 K/ps) and the multiscale shock technique (MSST) (8 km/s, 9 km/s and 10 km/s). The evolution of initial decay reactions, number of products and clusters were performed to reveal the differences in the decomposition mechanisms between crystalline and amorphous of DNAN. Initial molecules of crystals were consumed faster in constant temperature simulations, while initial molecules of amorphous were consumed faster at MSST simulations. The O-C bond breakage was the most important thermolysis reaction and dimerization reaction was the most important shock reaction. Dimerization, intermolecular hydrogen transfer, and intermolecular oxygen transfer occur only at constant temperature and MSST simulations, and direct dissociation reactions of OH groups occur only in the amorphous case. Products analysis showed that CH3O was very important product in all simulations. Clusters analysis showed that the number of clusters in the crystals was greater than in the amorphous case for all shock velocities at MSST simulations. The fitted activation energies showed that the crystalline case was more susceptible to thermal decomposition reactions, and the fitted the initiation pressures for crystalline DNAN was 13.58 GPa, which was higher than the experimental value. There was no doubt that the molecular packing style would affect their decomposition behaviors. These results could help to increase the understanding for decomposition mechanisms of crystalline and amorphous energetic materials.

Low-temperature growth of narrow optical gap highly conducting nc-Ge thin films with superior crystallinity involving dominant orientation

The nc-Ge thin films are grown at a moderately low temperature (∼220 °C) in rf PECVD via optimizing the GeH4 plasma with H2-dilution, within 97.5 ≤ D(H2)(%) ≤ 99.5. At elevated D(H2), while the bonded H-content in the matrix reduces, the film's crystallinity and dc conductivity increase. However, the optical band gap widens for 97.5 ≤ D(H2)(%) ≤ 98.5, via the elevated quantum confinement effect from the increased number of Ge-ncs of dimension below Bohr radius. Conversely, for D(H2) ≥ 98.5%, switching in the quantum effect in larger-sized Ge-ncs induces the band gap narrowing. Significantly reduced ultra-nanocrystalline-Ge (unc-Ge) component occupying the grain boundary zone, minimizes the contribution of grain-boundary defects. However, the persistent amorphous Ge matrix becomes highly defective and less dense, and those induce enhanced O-absorption from the ambient in the dominant Ge-Ox (x < 2) configuration. On increased crystallinity, the activation energies of dipole relaxation (ΔEτ) and resistance (ΔE) in the impedance data reduce dominantly in the a-Ge component than its nc-Ge counterpart, which occurs identically for the dc conductivity when the amorphous component in the matrix sharply disappears at increased D(H2) > 98.5%. A narrow band gap (∼0.90 eV), conducting (σd ∼3.0 ×10−2 S cm−1), and photosensitive nc-Ge network, involving dominant <111>-oriented Ge-ncs (∼35.2 nm) of enriched volume fraction (XC ∼90.2%), obtained at D(H2) ∼99.5%, seems extremely useful for need-based applications as a narrow band gap absorber layer in the bottom sub-cell of flexible high-efficiency cost-effective multijunction thin film solar cells.

Synergistic effect of polymers in stabilizing amorphous pretomanid through high drug loaded amorphous solid dispersion.

Pretomanid (PTM), an oral antibiotic used in the treatment of adults with pulmonary extensively drug-resistant, nonresponsive multidrug-resistant tuberculosis (MDR-TB). It is a poor glass former, that shows high recrystallization tendency from the amorphous and supersaturated state, resulting in low aqueous solubility and suboptimal absorption through the gastrointestinal tract. The present investigation aimed to develop high drug loaded ternary amorphous solid dispersions (ASDs) of PTM with improved stability and enhanced biopharmaceutical performance by utilizing a combination of polymers. The polymers were comprehensively screened based on drug-polymer miscibility and saturation solubility analysis. A combination of Hydroxypropyl Methylcellulose Acetate Succinate (HPMCAS-HF) and Polyvinylpyrrolidone K-30 (PVP K-30) showed synergism in drug-polymer miscibility as evidenced through pronounced depression in the melting endotherm of PTM. The Powder X-ray Diffraction (P-XRD) diffractograms of 30% w/w PTM loaded ternary ASDs displayed the halo pattern, contrary to the binary ASDs. Drug-polymer interactions (hydrophobic forces) involved between PTM and polymers were detected through Fourier Transform Infrared Spectroscopy (FT-IR) and Nuclear Magnetic Resonance Spectroscopy (13C-NMR) which contributed to the synergistic enhancement in solubility and dissolution of ternary ASDs with sustained release over 12h. Ternary ASDs demonstrated better in-vivo performance compared to the binary ASDs, showing a 4.63-fold increase in maximum plasma concentration. All ASDs remained stable and resisted phase separation during short-term stability studies for 3 months at ambient conditions. It was concluded that the hydrophobic and hydrophilic polymeric combination (HPMCAS-HF and PVP K-30, respectively) effectively prevented the crystallization and ensured sustained drug release with improved in-vivo absorption of PTM.

Balancing Polarization and Breakdown for High Capacitive Energy Storage by Microstructure Design.

The compromise of contradictive parameters, polarization, and breakdown strength, is necessary to achieve a high energy storage performance. The two can be tuned, regardless of material types, by controlling microstructures: amorphous states possess higher breakdown strength, while crystalline states have larger polarization. However, how to achieve a balance of amorphous and crystalline phases requires systematic and quantitative investigations. Herein, the trade-off between polarization and breakdown field is comprehensively evaluated with the evolution of microstructure, i.e., grain size and crystallinity, by phase-field simulations. The results indicate small grain size (≈10-35nm) with moderate crystallinity (≈60-80%) is more beneficial to maintain relatively high polarization and breakdown field simultaneously, consequently contributing to a high overall energy storage performance. Experimentally, therefore an ultrahigh energy density of 131 J cm-3 is achieved with a high efficiency of 81.6% in the microcrystal-amorphous dual-phase Bi3NdTi4O12 films. This work provides a guidance to substantially enhance dielectric energy storage by a simple and effective microstructure design.

Engineering a Hierarchy of Disorder: A New Route to Synthesize High-Performance 3D Nanoporous All-Carbon Materials*.

A new nanoporous amorphous carbon (NAC) structure that achieves both ultrahigh strength and high electrical conductivity, which are usually incompatible in porous materials is reported. By using modified spark plasma sintering, three amorphous carbon phases with different atomic bonding configurations are created. The composite consisted of an amorphous sp2-carbon matrix mixed with amorphous sp3-carbon and amorphous graphitic motif. NAC structure has an isotropic electrical conductivity of up to 12000Sm-1, Young's modulus of up to ≈5GPa, and Vickers hardness of over 900MPa. These properties are superior to those of existing conductive nanoporous materials. Direct investigation of the multiscale structure of this material through transmission electron microscopy, electron energy loss spectroscopy, and machine learning-based electron tomography revealed that the origin of the remarkable material properties is the well-organized sp2/sp3 amorphous carbon phases with a core-shell-like architecture, where the sp3-rich carbon forms a resilient core surrounded by a conductive sp2-rich layer. This research not only introduces novel materials with exceptional properties but also opens new opportunities for exploring amorphous structures and designing high-performance materials.

Stringlet excitation model of the boson peak.

The boson peak (BP), a low-energy excess in the vibrational density of states over the Debye contribution, is often identified as a characteristic of amorphous solid materials. Despite decades of efforts, its microscopic origin still remains a mystery. Recently, it has been proposed, and corroborated with simulations, that the BP might stem from intrinsic localized modes involving one-dimensional (1D) string-like excitations ("stringlets"). We build on a theory originally proposed by Lund that describes the localized modes as 1D vibrating strings, but we specify the stringlet size distribution to be exponential, as observed in simulations. We provide an analytical prediction for the BP frequency ωBP in the temperature regime well below the observed glass transition temperature Tg. The prediction involves no free parameters and accords quantitatively with prior simulation observations in 2D and 3D model glasses based on inverse power law potentials. The comparison of the string model to observations is more uncertain when compared to simulations of an Al-Sm metallic glass material at temperatures well above Tg. Nonetheless, our stringlet model of the BP naturally reproduces the softening of the BP frequency upon heating and offers an analytical explanation for the experimentally observed scaling with the shear modulus in the glass state and changes in this scaling in simulations of glass-forming liquids. Finally, the theoretical analysis highlights the existence of a strong damping for the stringlet modes above Tg, which leads to a large low-frequency contribution to the 3D vibrational density of states, observed in both experiments and simulations.

Enhancing thermal properties and surface quality of lappato glazed porcelain tiles through milling time optimization

AbstractIncreasing the surface quality of porcelain tiles, preferred in public, commercial, and living centers, where human density is high, is one of the crucial goals. Surface applications can be applied on the tiles produced as glazed and unglazed tiles in different versions. In lappato glazed tiles, staining-resistance is of great importance besides glossy-surface and wear-resistance. In this study, technical properties such as staining, chemical agent-resistance, color-parameters, thermal-behavior (heat microscopy), roughness, abrasion resistance, and microstructure of glazes (SEM/EDS) depending on the optimizing grinding time were examined with compared to standard lappato-glaze under the industrial conditions. It was observed that with the increase of the glaze grinding, the whiteness value and the increasing smoothness, and higher staining chemicals resistance and the glaze which has lower characteristic temperatures than the standard. As the surface roughness decreased due to grinding, the number and size of pores in the microstructure decreased. The glassy phase exhibited homogeneous distribution due to the dissolution of anorthite crystals.

Tailoring the Ni-O Microenvironment in Amorphous-Dominated Highly Active and Stable Zn/NiO for Hydrogen Sulfide Detection.

Amorphous metal oxide semiconductor (MOS) materials are endowed with great promise to modulate electronic structures for gas-sensing performance improvement. However, the elevated-temperature requirement of gas sensors severely impedes the application of amorphous materials due to their low thermal stability. Here, a cationic-assisted strategy to tailor the Ni-O microenvironment in an amorphous-dominated Zn/NiO heterogeneous structure with high thermal stability was developed. It was found that 6 mol % Zn incorporation into amorphous NiO can effectively preserve the amorphous-dominated NiO phase even at high temperature. After calcination, the amorphous oxide can only be converted to crystals partly thus leading to the formation of amorphous/crystalline compounds, and the content of the amorphous phase can be adjusted by changing the calcination temperature. This amorphous/crystalline configuration can induce more electron transfer from Ni to Zn species, leading to the formation of active Niδ+ (δ>2) centers. Ex situ XPS and in situ Raman spectroscopy studies proved that the generated Niδ+ species pronouncedly promote the electron transfer during the H2S adsorption process. The amorphous/crystalline-6 mol % Zn/NiO sensor exhibits exceptional hydrogen sulfide response (2 ppm, 3.23), outstanding repeatability (as long as 5 weeks), and low limit of detection (as low as 50 ppb), surpassing most reported nickel-based gas sensors such as the crystal nickel oxide prepared in this work. The response and detection limit of the latter is only (2 ppm, 1.89) and (0.05 ppm) respectively. Our work thus opens up more opportunities for fundamental understanding and modulating of highly active amorphous sensing materials.

Effects of amorphous phase and yttrium on flash sintering and microstructures of ZrO2–SiO2 ceramic nanocomposites

AbstractFlash sintering has been used to consolidate a wide range of ceramics and ceramic composites. However, flash sintering of ceramic nanocomposite with a substantial amorphous phase is rarely studied. Meanwhile, the effects of yttrium addition on the flash sintering behaviors and microstructures of ZrO2‐based ceramic nanocomposite remain unknown. Herein, ZrO2‐SiO2 crystalline‐amorphous ceramic nanocomposites (CACNs) with different contents of amorphous phase and two types of yttrium dopants were sintered by flash sintering. Results showed that the content of amorphous phase (SiO2) had significant effects on the flash sintering behavior. The CACN with 65 mol% SiO2 was nonflash sinterable due to the high electric resistivity of SiO2, whereas, the CACN with 45 mol% SiO2 can be flash sintered to high densification within 35 seconds. The flash‐sintered CACNs consisted of ZrO2 nanocrystallites distributed in an amorphous SiO2 matrix. Flash sintering enhanced the tetragonal‐to‐monoclinic phase transformation of ZrO2. In addition, influences of yttrium dopant on CACNs were also investigated. Yttrium dopants can rapidly dissolve in ZrO2 lattices and show a tetragonal phase stabilization effect during flash sintering. Firework‐like ZrO2 microcrystallites formed by dendritic growth were observed close to the cathode region, which was attributed to athermal electric field effects and the formation and aggregation of oxygen vacancies at the cathode region. The results would provide guidance for fabricating CACNs via flash sintering.

Construction of sub micro-nano-structured silicon based anode for lithium-ion batteries

The significant volume change experienced by silicon (Si) anodes during lithiation/delithiation cycles often triggers mechanical-electrochemical failures, undermining their utility in high-energy-density lithium-ion batteries (LIBs). Herein, we propose a sub micro-nano-structured Si based material to address the persistent challenge of mechanic-electrochemical coupling issue during cycling. The mesoporous Si-based composite submicrospheres (M-Si/SiO2/CS) with a high Si/SiO2 content of 84.6 wt.% is prepared by magnesiothermic reduction of mesoporous SiO2 submicrospheres followed by carbon coating process. M-Si/SiO2/CS anode can maintain a high specific capacity of 740 mAh g−1 at 0.5 A g−1 after 100 cycles with a lower electrode thickness swelling rate of 63%, and exhibits a good long-term cycling stability of 570 mAh g−1 at 1 A g−1 after 250 cycles. This remarkable Li-storage performance can be attributed to the synergistic effects of the hierarchical structure and SiO2 frameworks. The spherical structure mitigates stress/strain caused by the lithiation/delithiation, while the internal mesopores provide buffer space for Si expansion and obviously shorten the diffusion path for electrolyte/ions. Additionally, the amorphous SiO2 matrix not only servers as support for structure stability, but also facilitates the rapid formation of a stable solid electrolyte interphase layer. This unique architecture offers a potential model for designing high-performance Si-based anode for LIBs.

Deterministic quasi-continuous tuning of phase-change material integrated on a high-volume 300-mm silicon photonics platform

Programmable photonic integrated circuits (PICs) consisting of reconfigurable on-chip optical components have been creating new paradigms in various applications, such as integrated spectroscopy, multi-purpose microwave photonics, and optical information processing. Among many reconfiguration mechanisms, non-volatile chalcogenide phase-change materials (PCMs) exhibit a promising approach to the future very-large-scale programmable PICs, thanks to their zero static power and large optical index modulation, leading to extremely low energy consumption and ultra-compact footprints. However, the scalability of the current PCM-based programmable PICs is still limited since they are not directly off-the-shelf in commercial photonic foundries now. Here, we demonstrate a scalable platform harnessing the mature and reliable 300 mm silicon photonic fab, assisted by an in-house wide-bandgap PCM (Sb2S3) integration process. We show various non-volatile programmable devices, including micro-ring resonators, Mach-Zehnder interferometers and asymmetric directional couplers, with low loss (~0.0044 dB/µm), large phase shift (~0.012 π/µm) and high endurance (>5000 switching events with little performance degradation). Moreover, we showcase this platform’s capability of handling relatively complex structures such as multiple PIN diode heaters in devices, each independently controlling an Sb2S3 segment. By reliably setting the Sb2S3 segments to fully amorphous or crystalline state, we achieved deterministic multilevel operation. An asymmetric directional coupler with two unequal-length Sb2S3 segments showed the capability of four-level switching, beyond cross-and-bar binary states. We further showed unbalanced Mach-Zehnder interferometers with equal-length and unequal-length Sb2S3 segments, exhibiting reversible switching and a maximum of 5 (N+1,N=4\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$N+1,N=4$$\\end{document}) and 8 (2N,N=3\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$${2}^{N},N=3$$\\end{document}) equally spaced operation levels, respectively. This work lays the foundation for future programmable very-large-scale PICs with deterministic programmability.

Amorphization transition and electrical properties of La2−xCexCuO4 polycrystalline materials

In contrast to crystals, amorphous materials exhibit distinctive properties and applications due to their unique electronic structure and surface energy. Moreover, the amorphous modification of crystalline materials also results in numerous notable and unique properties. In this study, we propose the amorphous modification of polycrystal La2CuO4 with CeO2, examining the composition of the two phases and changes in the crystal structure. Our findings indicate that the degree of ordering of the La2CuO4 phase significantly decreases as the CeO2 content increases, leading to a resistivity increase in 3–4 orders of magnitude. Furthermore, within the 40–400 K, the transition of the Efros–Shklovskii variable range hopping (E–S VRH) transport mechanism between localized states to the Mott 3D VRH and the crossover around 230 K is observed. The method presented here has great potential in modifying polycrystalline materials by using amorphization to make a sudden increase in resistivity.

Unlocking the potential of spinel MnV2O4 for highly durable aqueous zinc-ion batteries

Aqueous zinc-ion batteries (AZIBs) have received comprehensive attention as promising candidates for large-scale energy storage owing to high security, low cost, and environmental friendliness. Developing appropriate cathode materials is of great significance for high-efficiency Zn2+ storage. Herein, we proposed an efficient in-situ electrochemical pretreatment strategy to unlock the potential of non-electrochemically active spinel MnV2O4via an irreversible phase reconstruction from crystalline structure to short-range ordered amorphous state. Specifically, the reconstructed electrodes not only deliver abundant active sites for Zn2+ ions accommodation, but also shorten diffusion paths for rapid reaction kinetics, thus achieving superior electrochemical properties. As revealed, the optimized electrodes present a prominent specific capacity of 445 mA h g−1 at 0.1 A g−1, a high capacity retention of 73.1 % over 2000 cycles at 5 A g−1, as well as exceptional energy density of 335 W h kg−1 and power density of 176 W kg−1 based on the mass of cathode. In addition, the reaction mechanism during Zn2+ ions storage process is systematically investigated by ex-situ X-ray diffraction and X-ray photoelectron spectroscopy. This in-situ electrochemical conversion mechanism sheds light on a new methodology of designing desirable cathode materials for aqueous ion batteries.

Choc-Tadalafil Fusion: Unlocking Solubility and Taste Harmony with ß-CD-Infused Medicated Chocolate.

The primary limitations of tadalafil in treating erectile dysfunction are its low solubility and unpleasant bitter taste, which ultimately result in inadequate patient adherence. The present study aimed to develop and characterize a medicated chocolate formulation containing Tadalafil and ß-CD (solubility enhancer) employing the concept of Design of Experiment (DoE) using chocolate as a user-friendly excipient. An inclusion complex was formulated by incorporating the drug into ß-CD using the kneading method for solubility improvement and also as a taste masker for Tadalafil. The ratio of drug: ß-CD inclusion complex was selected based on a phase solubility study. The inclusion complex was molded into a chocolate base and optimized using the DoE approach. Further, drug excipient interaction was evaluated by DSC and FTIR study. Phase solubility study suggested a 1:1 ratio of Tadalafil: β-CD for better solubility. DSC spectra suggested the conversion of crystalline structure into an amorphous state which indicates improvement of the drug solubility. DSC and FTIR studies revealed that there was no significant interaction between drug and excipients. Next, %CDR (cumulative drug release) at 30 min revealed the immediate effect of Tadalafil from chocolate formulation and free drug analysis (an unbound drug with ß-CD) proved reduced bitterness of the drug in the complex. Additionally, the medicated chocolate was found to be stable at room temperature as per stability study. β-CD was found to be a promising multifunctional excipient as a solubility enhancement carrier and taste masker for bitter-tasting drugs.

Susceptibility to Stress Corrosion Cracking of Selected Amorphous Polymer Materials in a Sea-Water Environment

Susceptibility to Stress Corrosion Cracking of Selected Amorphous Polymer Materials in a Sea-Water Environment

Thermal protection of steel using various ceramic-like fireproofing coatings systems: Comparative study

A comparative study on three types of fireproofing coatings -cementitious, perlite/vermiculite, and epoxy- was made to determine their effectiveness in protecting steel structures. The effects of these coatings on the external protection of steel were structurally, thermally, and mechanically studied. The prepared cementitious coatings endured the heat until "1200 oC" for 1 hour showing dimensions stability without deformation nor cracking during firing. Both cold crushing strength and bulk density measurements decreased with increasing the perlite and vermiculite percentages. Six of the prepared 48 perlite/vermiculite and epoxy coatings succeeded in bearing heat until "900 oC" for 3.5 hours sustaining the steel substrates' temperature below "60 oC" following "UL94 standard". This protective effect was due to the formation of a hard glassy phase on its surface isolating it from the heat by the action of the applied constituents. TGA and DSC techniques were performed for these samples, revealing that they gave a high residual weight from 63 to 88% at "900 °C". Performing the SEM test showed that only a physical reaction occurred before firing. The results concluded that the used ingredients, which have low prices and are locally available, are recommended for the fire protection of steel.

Identifying optimal amorphous materials for fluoride removal through Monte Carlo and neural network modeling

Identifying optimal amorphous materials for fluoride removal through Monte Carlo and neural network modeling