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Phosphogypsum is restricted as a building material because of its poor water resistance. In this study, phosphorus building gypsum, cement, and lime were used as the main materials, and water reducer and retarder were used as additives to prepare phosphorus gypsum cementitious materials under low water–cement ratio. Concurrently, the mechanical properties and hydration mechanism of phosphogypsum cementitious materials were investigated during both hydration and soaking processes, alongside a discussion on optimization strategies for enhancing their water resistance. The findings indicate that under low water–cement ratio conditions, rapid hydration of a substantial amount of phosphorus building gypsum occurs, leading to the formation of a spatial skeleton and significant enhancement in compressive strength. Some segments of the phosphorus building gypsum hydration process experience delay or cessation, while certain constituents of cement are densely packed, forming a compact system. Submerging in clear water gradually provides an adequate water environment, allowing for complete hydration of both phosphorus building gypsum and cement components, effectively filling the pores. Water immersion results in a material loss in the phosphogypsum cementitious system, leaving the pores formed after dissolution incompletely filled. In low water–cement ratio phosphogypsum cementitious systems, the secondary hydration process avoids exposure to a flowing solution environment, thereby circumventing material loss and achieving a complete and dense phosphogypsum cementitious system. [ABSTRACT FROM AUTHOR]

This study explores the viscoelastic, self-healing, and shape memory properties of poly(ε-caprolactone) (PCL), the ionomer EMAA-Zn, and their blends in different proportions (70/30, 50/50, 30/70) using torque rheometry, rheological analysis, FTIR spectroscopy, X-ray Diffraction, Dynamic Mechanical Analysis (DMA), scanning electron microscopy (SEM), and shape memory evaluations. The objective is to investigate the synergistic effects of ionic bonds, clusters, and PCL diffusion in PCL/EMAA-Zn blends for potential applications requiring thermo-responsive shape memory and self-healing capabilities. Rheological analysis identifies distinctive viscoelastic properties, with PCL/EMAA-Zn (30/70) exhibiting commendable scratch healing capabilities and relatively strong mechanical properties. FTIR spectra confirm characteristic absorption bands, while DMA highlights transitions corresponding to PCL melting and order–disorder shifts in EMAA-Zn clusters. XRD patterns demonstrate the persistence of crystalline structures in blends. SEM images reveal morphological differences, with the (50/50) blend displaying a co-continuous structure. Shape memory evaluations showcase promising results in both water immersion and torsion mode, emphasizing the potential for PCL/EMAA-Zn blends in shape recovery applications. Furthermore, self-healing analyses indicate superior performance in the blends, particularly (50/50) and (30/70) compositions, showcasing healing efficiencies of 90% and 96%, respectively. In conclusion, the study positions PCL/EMAA-Zn blends as promising materials for applications requiring thermo-responsive shape memory and efficient self-healing, showcasing the intricate interplay of ionic interactions, supramolecular bonds, and PCL diffusion in achieving optimal properties. [ABSTRACT FROM AUTHOR]

This study investigates the time-dependent behavior of sisal fibers under sustained uniaxial tensile loads in different environments, addressing gaps in understanding beyond quasi-static conditions. Testing involved immersion in water and alkaline solutions (0.5 M and 1 M NaOH) to simulate service conditions. Stress levels were set at 8, 16, and 33% of ultimate tensile strength (1, 2, and 4 N). Modifications, including alkaline treatment, styrene-butadiene polymer coating (50% and 100% v/v), and tannic acid functionalization, were applied to explore their impact on fiber creep behavior. Results indicated a logarithmic creep pattern, with a high constant rate in primary creep followed by secondary creep. Sisal fibers exhibited significant deformation under sustained load, and time-dependent strain varied with the applied load. High humidity increased the global rate of fiber deformation, resulting in elevated time-dependent strain levels. All treatments effectively reduced fiber creep strain, with tannic acid-functionalized fibers showing the best results. Subsequent quasi-static uniaxial tests assessed the mechanical response and durability of both pristine and modified fibers. Findings revealed that, compared to untreated fibers, modified sisal fibers demonstrated improved maintenance of mechanical properties after sustained-load tests in aggressive environments. This research contributes with valuable insights into the time-dependent behavior of sisal fibers and highlights the efficacy of various modifications in enhancing their durability under different loading conditions and environments. [ABSTRACT FROM AUTHOR]

The current work examines the durability of composites reinforced with glass fibre woven fabric as well as non-crimp fabrics (NCF) immersed in water at 43, 65 and 93 °C for up to 2.5 years. Low velocity normal impact has been induced at various time intervals before and after water immersion at energy levels of 2.5, 5 and 10 J. Following impact the plates were tested statically in compression to determine the residual strength for assessment of damage tolerance. The compression strength suffered significant reductions from the water absorption and the low velocity impact with values being dependent to the time of immersion and the water temperature. A parallel behaviour was monitored, in terms of strength reduction over time, of plates impacted prior to water immersion with the plates that contain no damage. For specimens where impact damage introduced after water immersion lower compression-after-impact (CAI) strength was observed at the same energy levels. An increase in damage diameter was evident, regardless the reinforcement type, though the gradually produced greater density of through thickness damage was responsible for the significant lower compression strength values. The presence of 0° fibres for the NCF composites as the main load bearing element dictated the sensitivity to impact as well as the corresponding residual strength. For composites with woven reinforcement, damage was contained and localized by the fabric weave and effective stress redistribution seemed to be the mechanism for the relatively higher residual strengths obtained. A semi-empirical model has been used with high accuracy in fitting the given experimental data and draw conclusions from the comparisons. [ABSTRACT FROM AUTHOR]

In this study, physically exfoliated graphene was embedded in zinc-rich epoxy coatings with different zinc contents to study the corrosion protection of graphene-modified zinc-rich epoxy (GZRE) coatings to steel substrates under high-temperature and high-concentration NaCl solution. Electrochemical impedance spectroscopy and open-circuit potential were conducted to investigate the corrosion resistance of GZRE coatings with different zinc contents under intact and damaged conditions. The supporting evidence was also provided by surface morphology, cross-sectional morphology, scratch morphology, and salt spray experiment. The contact mode of zinc particles–graphene–zinc particles can be formed between graphene and zinc particles in GZRE, thus improving the electrical connection between zinc particles. The role of graphene in improving the barrier effect and cathodic protection performance of GZRE depends on the zinc content in the coating. Moreover, it was discovered that highly active zinc particles could effectively attenuate the galvanic corrosion effect between graphene and steel substrate. This research will provide promising enlightenment for the application of graphene-modified zinc-rich epoxy coatings for the corrosion protection of steel substrates under high-temperature and high-concentration NaCl solution. [ABSTRACT FROM AUTHOR]

Silk fibroin (SF) is a natural and biocompatible polymer that is obtained from silk cocoons or from silk fibrous waste. In this study, aqueous solutions of SF were obtained from silk fibrous waste (SFW) and subjected to concentration by reverse dialysis with polyethylene glycol (PEG) or freeze-drying with subsequent resolubilization prior to processing via electrospinning. The regenerated SFW was stored at 4 °C, and its stability during refrigeration was investigated in terms of structural changes using visual monitoring and attenuated total reflectance Fourier transform infrared spectroscopy (FTIR-ATR) until gelation occurred. The electrospun nonwovens produced through both concentration processes were post-treated using methanol (MeOH), by immersion in the liquid solvent and by exposure to a saturated atmosphere. The electrospun nonwovens before and after post-treatments were characterized using scanning electron microscopy (SEM), FTIR-ATR, and differential scanning calorimetric (DSC). SFW re-suspended after the PEG concentration remained liquid and retained its electrospinnability for 21 days, while the resolubilized SFW solution after freeze-drying formed a gel after only 7 days. During these processability windows, it was possible to obtain SFW homogeneous fibers. Increasing solution storage time was correlated with increased fiber diameter and reduced porosity of the electrospun nonwovens. The fibers treated with MeOH, both liquid and vapor, showed an increase in diameter and crystallinity, as well as a reduction in their apparent porosity. This work contributes new information about pre- and post-processing of SFW aqueous solutions for electrospun SFW nonwovens, expanding the potential of a by-product of silk production in value-added biomaterials production. [ABSTRACT FROM AUTHOR]

The influence of water immersion and silane treatment on the AC breakdown and the complex dielectric response of polypropylene/nano-aluminium nitride (PP/nano-AlN) composites has been investigated. The as-received filler was examined to have a nanoscale particle distribution with a hexagonal shape and slight hydrolysation. Grafting the aluminium nitride with an octyl silane reduces the weight increase in samples filled with 10 wt% of aluminium nitride during water immersion by 3, from 0.29 to 0.09%. The results suggest that the AC breakdown strength and complex permittivity of "wet" composite samples are related to the silane treatment of the nanofiller. The AC breakdown strength of octyl silane-treated samples after 9 days of water immersion shows comparable results to the dry samples, while a reduction can be seen on non-treated samples. Although silane-treated samples still show an increased dielectric loss at low frequency after water immersion, a significant reduction in low-frequency dispersion of real and imaginary permittivity can be seen when compared to the non-treated composites. This indicates that significant gains can be obtained for PP/nano-AlN composites by suitable silane treatments. [ABSTRACT FROM AUTHOR]

This study explored the improvement of the physicochemical properties (mechanical resistance, water uptake, swelling, etc.) of Nafion membranes by cellulose nanocrystals (CNCs). These composite membranes were prepared from Ramie and Tunicate nanocrystals with respective aspect ratios of about 28 and 106. It was demonstrated that, regardless of the type of nanocrystals, increasing the cellulose weight content from 0 to 10 wt% increased the water uptake and the thickness swelling and decreased the in-plane swelling of the composite membranes during water immersion. The mechanical performances of the composite membranes (tensile strength, elongation at break and Young's modulus) were also enhanced, with the best compromise for Tunicate nanocrystals found to be 5 wt%. The effect of thermal annealing up to 150 °C on the Nafion-Tunicate 5 wt% composite was tested and compared to that of pure Nafion. With thermal annealing, a small decrease in water uptake capacity, protonic conductivity, ion exchange capacity and hydration number was observed for both membranes. At the sub-molecular level, FTIR data suggest that the heat treatment of Nafion-Tunicate membranes induces cross-linking reactions between sulfonic groups of Nafion chains and surface functional groups of CNCs, leading for example to sulfonic ester links. The exothermic peak observed by DSC can assign an increase of the crystalline phase of Nafion chains and especially in the vicinity of CNCs. All cross-linkages led to an improvement in the mechanical resistance of the membranes when thermal annealing was below 130 °C. [ABSTRACT FROM AUTHOR]

Omniphobic coatings which can efficiently diminish the interfacial reactions between the underlying substrates and foreign liquids present broad technological impacts and enormous potential applications, whereas the current prepared superamphiphobic surfaces are constrained to their weak robustness owing to the vulnerability of the sophisticated hierarchical structures. Herein, we employed oxidative polymerization method to graft polyaniline (PANI) nanofibers on arbitrarily shaped surfaces that further modified with perfluoroalkylthiol and infiltrated with perfluoropolyether lubricant, constructing a slippery lubricant-infused porous surfaces (SLIPS). With the enlargement of the polymerization time, the coverage degree of PANI coating on the glass surface gradually increased and their transmittance reduced simultaneously. Meanwhile, the influences of the structure geometry and surface chemistry on the slippery behavior of foreign liquids on the SLIPS were investigated, further verifying that the synergetic effect of the adequate texture roughness and matched surface chemistry is the prerequisite for preparing steady and defect-free lubricant layer. Moreover, the prepared SLIPS could be applied in various promising applications such as anti-fogging, anti-fingerprint, three-dimensional droplet manipulation and crude-oil lossless transportation. More importantly, the lubricant layer remained stable on the surfaces after long-term storage in high/low temperature, water immersion and ultraviolet irradiation, and displayed superior mechanical resistance to water impact, sandpaper abrasions and knife scratches. Therefore, this strategy for fabricating nepenthes-inspired lubricant-infused surfaces is expected to further promote the cognition and manufacture of multifunctional omniphobic materials. [ABSTRACT FROM AUTHOR]

This study is aimed to evaluate the galvanic corrosion of a newly designed TiMg dental implant. The TiMg composite was tested in two forms: (1) cylinders (TiMg cyl) and (2) dental implants (TiMg DI). Surface roughness was measured using a confocal microscope. The electrochemical behavior was determined in a Hank's balanced salt solution (HBSS) by the open-circuit potential (OCP), potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS) measurements. Surfaces after corrosion were examined by a scanning electron microscope (SEM) equipped with an energy-dispersive X-ray spectrometer (EDS). OCP of TiMg cyl and TiMg DI increased in the noble direction, indicating the formation and growth of a base film on their surfaces. After 2-h immersion, TiMg cyl had higher values of iCorr and RCorr compared with those of TiMg DI. After 24-h immersion, a prominent reduction in the values of iCorr and RCorr was observed, and ECorr shifted positively. The Nyquist plots of TiMg cyl and TiMg DI show capacitive loops that tended to close after 2-h exposure. As the time extended, TiMg DI showed higher corrosion resistance compared with that of TiMg cyl, and the linear diffusion response arose from the formation and dissolution of chemically non-stable by-products caused by the hydrogen evolution. In such a case, the involved reaction was controlled by charge transfer and diffusion processes. The formation of a film composed of stable CAp species that attached directly to the surface and chemically non-stable by-products that included (Mg3(PO4)2) and Mg(OH)2 was demonstrated. To conclude, the obtained results revealed that TiMg DI of a complicated threaded design had a more stable passive film and higher corrosion resistance in HBSS compared with those of TiMg cyl of a cylindrical design. These findings have the utmost importance for the fabrication of dental implants. [ABSTRACT FROM AUTHOR]

Manganese oxide/carbon nanotube (CNT) composite films on graphite were prepared by growing CNTs on the substrate using chemical vapor deposition (CVD), followed by immersion in an aqueous solution of potassium permanganate. The CVD growth created favorable conditions for deposition of the oxide on the electrode, and an aligned porous structure of the composite films, which originated from the CNT growth, could be managed. Electrochemical behaviors of the CNT and the composite films for supercapacitors were studied in 1 M NaSO solution. While the oxide deposition in the CNT films was identified as contributing to capacitance enhancement, it was also found that a mild heat treatment could improve performance of the composite films. [ABSTRACT FROM AUTHOR]

This study discussed the effects of jute fiber content and hot water immersion on the tensile properties of jute fiber reinforced polypropylene (PP) composites. The jute/PP composite with different fiber contents was molded by injection molding by dry-blending of jute/PP and neat PP pellets in various mix ratios. Firstly, the quasi-static tensile test was performed. Then the specimens were aged in hot distilled water at 80 °C. After the fixed periods of aging, the changed weight and the tensile properties were investigated. It is found that with the increase of the jute fiber content, the tensile modulus is increased lineally. However, referring to the tensile strength, it is increased firstly followed by a decreased when the jute weight percent is over 30. Additionally, it is found that the weight gain by water absorption was significantly affected by the fiber content. The specimens with the jute fiber content of or over 30 wt% absorbed water easily and significant material loss by aging was also occurred. The tensile strength after aging decreased remarkably in these specimens with the jute fiber content of or over 30 wt%, and all the jute/PP composites showed the lower strength than neat PP after the aging of 1000 h. It is considered that the hydrophilic property of natural fiber decreases the resistance of the composite in humidity environment. [ABSTRACT FROM AUTHOR]

The microstructure, compressive properties and in vitro degradation behavior of as-cast Mg alloys with high Zn or Ca content were investigated. The results showed that the addition of Ca (1 wt%) to Mg–5Zn or Zn (1 wt%) to Mg–5Ca changed the shape, distribution, volume fraction and the type of second phase. When 1 wt% Ca was added to Mg–5Zn alloy, the second phase changed from Mg7Zn3 to Ca2Mg6Zn3 phase and it was distributed from granular formation to a continuous network structure. While the second phase was changed from Mg2Ca in Mg–5Ca alloy to the coexistence of Mg2Ca(Zn) and slight Ca2Mg6Zn3 phase in Mg–5Ca–1Zn alloy. The second phase exhibited a continuous network distribution in both of Mg–5Ca and Mg–5Ca–1Zn alloys, but the width of Mg2Ca(Zn) phase was reduced obviously after adding 1 wt% Zn to Mg–5Ca alloy. The compressive test revealed that Zn element was contributed to the promotion of ultimate compressive strength and fracture elongation, while Ca element was beneficial for improving the yield strength of Mg alloys. The immersion test proved that the weight loss of Mg–5Zn–1Ca was the highest, followed by Mg–5Zn, Mg–5Ca and Mg–5Ca–1Zn alloy. The Mg–5Zn-based alloys suffered severe pitting, while Mg–5Ca-based alloy exhibited a relatively uniform corrosion. The Ca addition accelerated the corrosion of Mg–5Zn alloy due to the expansion of potential difference between second phase and Mg matrix, while Zn addition reduced the micro-galvanic corrosion of Mg–5Ca alloy due to the lowest potential difference between Mg2Ca(Zn) phase and Mg matrix. [ABSTRACT FROM AUTHOR]

Simple methods for the determination of refractive indices of transparent polymers and inorganic and organic solids of irregular geometry or with scratched or corrugated surfaces are rare. A classical procedure is based on the invisibility of a body immersed in a liquid with the same refractive index as that of the body. In order to avoid the laborious procedure connected with the search for a liquid with matching refractive index and to find an approach which is independent of the observation by eye, we describe here a modified immersion method which allows the ready determination of the refractive index of solids. The present method is based on the interpolation of the maximum transmission (nTmax) of a solid immersed in liquids with different, typically non-matching, refractive indices. Illustrations with quartz glass, crown glass and poly(vinylidene fluoride) (PVDF) films showed thatnTmax can be determined with a reproducibility of ± 0.003. By comparison with refractive indices determined by ellipsometry, it was concluded that the refractive index of a solid can be determined with the modified immersion method within an accuracy better than ± 0.01 when systematic errors resulting from the fit method are also taken into consideration. [ABSTRACT FROM AUTHOR]

In this study, the corrosion behaviour of several aluminium alloys in ethanol fuels was investigated by immersion and polarization tests. The corrosion properties of cast aluminium alloys (Al-17wt%Si-4wt%Cu-Mg, Al-8wt%Si-3wt%Cu, Al-7wt%Si-Mg and Al-17wt%Si-4wt%Cu-Mg with a chemically deposited nickel layer) in ethanol blended gasoline fuels were examined at various ethanol and water contents and various temperatures. Electrochemical and gravimetric measurements revealed a pronounced acceleration of the corrosion process above the boiling point. Additions of water restrain the corrosion. Increasing the ethanol content and the temperature leads to a higher corrosion sensitivity of the aluminium alloys. Furthermore, the nickel layer is very protective in all tested fuels. For aluminium alloys, a theory of the corrosion process in ethanol blended gasoline fuels is proposed. [ABSTRACT FROM AUTHOR]

Conductive elastic fabrics are desirable in wearable electronics and related applications. Highly elastic conductive polyamide/lycra knitted fabric was prepared using intrinsically conductive polymer poly (3,4-ethylenedioxythiophene) (PEDOT) blended with polyelectrolyte poly (styrene sulfonate) (PSS) using easily scalable coating and immersion methods. The effects of these two methods of treatments on uniformity, electromechanical property, stretchability, and durability were investigated. Different grades of waterborne polyurethanes (PU) were employed in different concentrations to improve the coating and adhesion of the PEDOT:PSS on the fabric. The immersion method gave better uniform treatment, high conductivity, and durability against stretching and cyclic tension than the coating process. The surface resistance increased from ~ 1.7 and ~ 6.4 Ω/square at 0% PU to ~ 3.7 and ~ 12.6 Ω/square at 50% PU for immersion and coating methods, respectively. The treatment methods as well as the acidic PEDOT:PSS did not affect the mechanical properties of the fabric and the fabric showed high strain at break of ~ 650% and remained conductive until break. Finally, to assess the practical applicability of the treated fabric for wearable e-textiles, the change in surface resistance was assessed by cyclically stretching 10 times at 100% strain and washing in a domestic laundry for 10 cycles. The resistance increased only by a small amount when samples were stretched cyclically at 100% strain, and the samples showed good durability against washing. [ABSTRACT FROM AUTHOR]

Influence of static compression loading on the degradation behaviors of polylactic acid-based composite reinforced with 20 vol% magnesium alloy wires (MAWs) is investigated. The external stress would enhance the degradation of the composite. As the applied stress is increased from 1 to 3 MPa, the overall degradation rate goes up. After immersion for 30 days, the degradation rate of PLA matrix in the composite at the stress level of 3 MPa is about 1.46 and 2.4 times those at 1 and 0 MPa (unloading condition) while the bending strength retention is 0.73 and 0.63 times those of the latter ones. The relationship between the degradation rate of PLA matrix in the composite and the external compression stress is further elucidated. The external stress deteriorates the strength retention of the composite but a high MAWs content could mitigate the deterioration. [ABSTRACT FROM AUTHOR]

Akermanite (Ak) has promising prospects as an innovative bio-ceramic for bone regeneration. The most common fabrication methods to produce pure Ak powders are long-lasting synthesis routes followed by calcination at high temperatures. This study focuses on the use of microwave irradiation of a solution to provide initial Ak-based powder product that after subsequent heat treatment changes to pure Ak powder. The novel process named microwave-assisted sol–gel method actually speeds up the initial and final stages of pure Ak powder production when compared to the traditional sol–gel with later heat treatment stage. The viscous solution containing magnesium nitrate hexahydrate, calcium nitrate tetrahydrate, and tetraethyl ortho-silicate was microwave irradiated for three minutes. X-ray diffraction showed that the microwaved products after calcination treatment at 1200 °C for 4 h were mostly made of Ak and a small amount of merwinite. However, by increasing the calcination treatment to 1300 °C, single-phase akermanite powder was achieved. By subjecting same precursor and subsequent heat treatments, the typical sol–gel method did not yield pure Ak powder. Thermal analyses and scanning electron microscopy examinations showed that the Ak crystallization temperature was lower in the case of the microwave irradiated product than in the conventional sol–gel route. The microwave irradiated product after calcination showed a porous structure formed by necking between the powder particles with a mean particle size of 2 µm. The results of the in vitro bioactivity evaluation indicated that synthesized Ak was bioactive through proving the formation of hydroxyapatite (HAp) on the surface of pure Ak disc after 7 days of immersion in simulated body fluid (SBF). The cell adhesion findings showed that MG-63 cells adhered and spread well on the Ak disc, suggesting that Ak discs possess good biocompatibility. The results of the MTT assay demonstrated that the cell proliferation of osteoblast-like MG-63 cells was enhanced with the increase in culture time. Our in vitro bioactivity, cell morphology, and adhesion evaluations and in vitro biocompatibility assessment suggested that Ak powders were bioactive and cytocompatible and have a great potential to be selected as an ideal candidate for bone tissue engineering applications. [ABSTRACT FROM AUTHOR]

Twin-roll cast magnesium has a fine-grained microstructure and exhibits relatively high strength and ductility. However, hydrogen-induced embrittlement in magnesium alloys can limit the mechanical properties substantially and can lead to sudden and unpredictable failure. In this study, embrittlement is determined by means of slow strain rate tests (SSRT) and instrumental indentation tests (IIT). The latter enables analysis of embrittlement under the suppression of crack propagation mechanisms and surface influences (e.g. notch effects due to pitting) and is a new technique for the investigation of hydrogen embrittlement (HE). In this study, the influence of immersion time and elastic deformation on the HE of twin-roll cast and heat-treated magnesium sheets (AZ31) was analysed. Distilled water and two NaCl solutions (0.05 and 0.5 wt%) served as analysing media. It is shown that both influencing factors significantly affect the rate and the degree of HE. Relatively short immersion in distilled water led to a substantial decrease in strain and an increase in brittleness, even without external mechanical loading. In contrast, strength was not affected by immersion in water and the resulting HE. In comparison to immersion in distilled water, immersion in sodium chloride solution led to a total loss of plasticity and a decrease in strength during SSRT without a distinct increase in embrittlement during IIT. Analysis by X-ray diffractometry did not determine a detectable amount of magnesium hydrides in the embrittled AZ31 structure. [ABSTRACT FROM AUTHOR]

In this study, we investigated the thermodynamics and experimental performance of Al, Zr, and Ce species under anode and cathode gas conditions in Li/K carbonate at 650 °C. Among the Al, Zr, and Ce species investigated, we found that lithium aluminate (LiAlO), lithium zirconate (LiZrO), and cerium/ceria oxide (CeO) were the most stable materials. Experimentally, we performed immersion tests in molten (Li/K)CO at 650 °C to evaluate the phase and microstructure stabilities of these materials. The γ-LiAlO phase transformation, determined using X-ray diffractometry, was dependent on the immersion time. We performed similar measurements for α-LiAlO, LiZrO, and CeO materials in molten Li/K carbonate at 650 °C. From immersion tests, the presence of the α-LiAlO phase revealed that phase transformation of γ-LiAlO occurs in Li/K carbonate melts under cathode gas atmospheres; in contrast, no phase transformation was evident after immersion of the pure α-LiAlO phase in molten carbonate for 5,000 h. Furthermore, we found that LiZrO and CeO were stable phases after immersion in molten carbonate at 650 °C, under both anode and cathode gas atmospheres, for more than 5,000 h. [ABSTRACT FROM AUTHOR]

TiO2 foam-like scaffolds with pore size ~300 μm and >95% porosity were fabricated by the foam replication method. A new approach to improve the structural integrity of the as-sintered foams, which exhibit extremely low compression strength, was explored by coating them with poly-( d, l-lactic acid) (PDLLA) or PDLLA/Bioglass® layers. The PDLLA coating was shown to improve the mechanical properties of the scaffold: the compressive strength was increased by a factor of ~7. The composite coating involving Bioglass® particles was shown to impart the rutile TiO2 scaffold with the necessary bioactivity for the intended applications in bone tissue engineering. A dense hydroxyapatite layer formed on the surface of the foams upon immersion in simulated body fluid for 1 week. [ABSTRACT FROM AUTHOR]

The influence of the fiber/matrix interface of pultruded glass fiber-reinforced polymer (GFRP) composites exposed to hygrothermal environments, including deionized water immersion and saltwater immersion at 20 ± 5 °C, 30 ± 1 °C, and 60 ± 1 °C for 180 days, was investigated. The effect of moisture absorption on tensile properties was discussed. After 180 days of immersion in deionized water, tensile strength and modulus of specimens decreased 25.7% and 26%, whereas the equivalent respective losses were 2.1% and 18.2% for specimens immersed in saltwater. The short-beam-shear test and the single-fiber fragmentation test were selected to reflect the degradation of macro- and micro-interfacial properties, respectively. After 180-day immersion in deionized water and saltwater at 60 ± 1 °C, the inter-laminar shear strength of specimens decreased 28.8% and 18.5%, respectively, and the corresponding interfacial shear strength decreased 53.2% and 23.5%, indicating that the diffusion rate of micro-interface was higher than that of macro-interface in the fiber direction. Immersion in all media leads to pronounced degradation in tensile strength, modulus, and inter-laminar shear strength. Furthermore, based on the change of interfacial strength and Weibull distribution, a prediction model was proposed to describe the degradation trends and temperature effects on ultimate bearing capacity of pultruded GFRP composites in hygrothermal environments. [ABSTRACT FROM AUTHOR]

In this work, comparative studies of the corrosion behavior of titanium manufactured by powder metallurgy (porous) and traditional technology (wrought) in aqueous solutions of hydrochloric and sulfuric acids of various concentrations were performed. Electrochemical, static immersion tests, and microstructural characterization pursued an influence of acid concentration on corrosion resistance and corrosion behavior. As expected, porous titanium had worse electrochemical performance and corrosion rate than non-porous wrought titanium in the studied acids; the presence of pores in titanium accounts for this. According to SEM and EDX analysis of corroded titanium surfaces, the corrosion mechanisms and their main differences for porous and non-porous wrought titanium were established. The safe use of porous titanium in sulfuric acid in the concentration range above 40% and up to 60% was confirmed. It was determined that the use of porous titanium in hydrochloric acid be limited due to its tendency to pitting. To improve the anticorrosion properties of porous titanium in hydrochloric acid, it is recommended to reduce the negative effect of pores, for example, by surface modification. This work demonstrates the range of acid concentrations beneficial for the operation of porous titanium. It provides referenceable data for designing and manufacturing products in the chemical, metallurgical, and other branches of industry. [ABSTRACT FROM AUTHOR]

The movement of water molecules at the atomic scale within the calcium silicate hydrate (C–S–H) gel pores serves a dual role: it creates an environment for harmful chemical reactions within the pores and functions as a carrier for the transport of detrimental ions, thereby affects the mechanical properties and durability of cementitious materials. However, direct experimental observation poses substantial challenges. This study offers new insights into how temperature (253 K, 273 K, 293 K, and 313 K) affects the capillary transport of water molecules in epoxy-modified C–S–H. The findings demonstrate that the pore size undergoes continuous changes during immersion due to epoxy clustering or detachment, resulting in three scenarios: narrowing of epoxy/C–S–H channels (253 K, 273 K), channel blockage (293 K), and complete detachment (313 K). Moreover, the interactions between water molecules and epoxy lead to epoxy detachment or cluster formation on the C–S–H surface. As the temperature increases, the interaction between C–S–H and cross-linked epoxy resin weakens. The coordination between C–S–H and epoxy resin decreases, while the coordination with water increases. This paper provides valuable insights into the transport behavior of liquids within the epoxy-modified C–S–H pores of cement-based materials. It contributes to a better understanding of how liquids move and interact within the modified pore structure, which is beneficial for enhancing the performance and properties of cement-based materials. [ABSTRACT FROM AUTHOR]

Aiming at deficiencies in non-degradable stents for benign common bile duct obstruction, the magnesium (Mg)-based braided stents were developed with one monofilament as a pilot research in this paper. We designed stents with the different monofilament diameter, braided-pin number and surface treatment systematically to study the mechanical and degradation behaviors. The results suggest the fluorinated Mg stents and them with polycaprolactone (PCL) coating can achieve the compression force of 3.35–11.07 N and 11.09–24.08 N, and even maintain 3.10–10.43 N for 3 days immersion and 3.11–9.37 N for 20 days immersion respectively. PCL coating on monofilament can provide significantly better compression force and corrosion resistance. By comparison with the stent in clinic, these Mg stents are expected to meet the demand of the radial compression force and implantation time. Furthermore, the degradation occurs at the ends preferentially for all stents, but for stents without PCL coating, the intersections of wire-mesh are also the area easily corroded. Additionally, the result of the compression test indicates the radial compression force is improved with the increase of monofilament diameter and pins number, but the recovery capability decreases slightly. [ABSTRACT FROM AUTHOR]

Cubic garnet of nominal composition LiLaZrO (LLZO) is of interest as a possible electrolyte in a Li-metal halide battery composed of molten Li and an insoluble metal halide as electrodes operating in the temperature range of ~300-350 °C. As a consequence, the chemical stability of LLZO with molten Li in this temperature range was investigated. After heating in molten Li, the LLZO surface had undergone chemical coloration. X-diffraction, X-ray photoemission spectroscopy, electron paramagnetic resonance, and heat-treatment experiments suggest that chemical coloration is a result of the formation of color centers, composed of an electron trapped at an oxygen vacancy. It was also observed that after immersion in molten Li that LLZO exhibited intergranular cracking. It is believed that cracking results from stresses generated from an increased Li content, gained during immersion. [ABSTRACT FROM AUTHOR]