Search Results (22)

This study addresses the corrosion problem of refractory materials during high-temperature molten treatment of pharmaceutical waste salt, and systematically investigates the interface behavior and corrosion mechanism of MgO-based refractory materials in simulated pharmaceutical waste salt (65 wt% NaCl-30 wt% Na₂SO₄-5 wt% CaCO₃). Through sessile drop wetting infiltration experiments, static corrosion tests (950 °C and 1150 °C/48 h), combined with SEM-EDS, XRD characterization, and FactSage thermodynamic calculations, the corrosion resistance of high-purity MgO phase (HM-97) refractory materials and magnesium–aluminum spinel composite phase (MA-85) refractory materials was compared and analyzed. The results show that due to the fine periclase grains and rich grain boundaries, the molten salt infiltration rate of HM-97 material in the 644–800 °C range is significantly higher than that of MA-85. After corrosion at 950 °C, HM-97 and MA-85 formed 47 μm and 53 μm transition layers respectively, and the HM-97 surface generated Ca₃Mg(SiO₄)₂ phase leading to uneven corrosion morphology. At 1150 °C, HM-97 produced long cracks and the transition layer thickness remained almost unchanged due to dissolution, while MA-85 formed an approximately 72 μm transition layer and a dense metamorphic layer. Phase analysis and thermodynamic calculations suggest that the MgAl₂O₄ phase in MA-85 is likely stable at high temperatures, which appears to effectively prevent molten salt infiltration and contribute to forming a protective metamorphic layer, thereby potentially enhancing the material’s corrosion resistance. The MgAl₂O₄ phase is proposed to improve the service performance of MgO-based refractory materials in the molten pharmaceutical waste salt environment. Full article

Objective: This work aims to reduce the surface tension of an aluminum–silicon alloy melt by adding different amounts of the Zn element, thus improving the coatability and coating quality of hot-dip aluminum plating on steel plates. Method: Wetting experiments were conducted at 1023 K using a modified sessile drop method. Conclusions: The addition of the Zn element can reduce the surface tension of the Al-Si alloy, thus decreasing the wettability of the Al-Si alloy. Zn vapor can break down the surface oxide film to expose the fresh melt. The wettability of the Al-10Si alloy on interstitial-free (IF) steel and surface tension were investigated using the modified sessile drop method at 1023 K. Axisymmetric Drop Shape Analysis software was utilized to calculate the contact angles of the Al-10Si-xZn/Al₂O₃ and Al-10Si-xZn/IF steel systems (x ranges from 0 wt.% to 5 wt.%). Moreover, the microtopography and microstructure of surfaces and cross-sections were analyzed by means of an energy-dispersive spectrometer and scanning electron microscope. The results indicated that the surface tension of the alloy melt gradually decreases with an increase in Zn content, ranging from 874 to 760 mN/m. The contact angle of the Al-10Si-xZn alloy melt on IF steel also progressively decreases with increasing Zn content, which is attributed to the lower surface tension of Zn. This study also discovered that the Zn element can disrupt the oxide film of the Al-10Si alloy, exposing the fresh melt and thereby reducing the surface tension of the alloy liquid, thus enhancing wettability. The addition of Zn might be capable of improving the hot-dip aluminizing coatability of steel plates and the quality of the coating. Full article

The design and fabrication of metal matrix materials (MMCs), as well as the densification and joining of ceramic matrix composites (CMC), are still very challenging. For SiC- and C-based composites, liquid-assisted processing routes, such as the spontaneous infiltration process, emerge among the most cost-effective processes. To succeed in Ir-Si/SiC refractory composite fabrication by spontaneous infiltration, the wetting characteristics of the Ir-Si/SiC system, the surface and transport properties (surface tension and viscosity) of liquid Ir-Si alloys, and microstructural evolution at the interfaces formed between solid SiC (or C) with Ir-Si melt, have been carefully examined. Specifically, the wettability and interaction phenomena occurring at the Si-Ir eutectics/SiC interface as a function of temperature were investigated in the temperature range of T = 1350–1400 °C by the sessile drop method under an inert atmosphere with reduced oxygen content, and the results are presented and discussed in this paper. Taking into account the thermodynamics of the Si-C-Ir system, the interfacial phenomena and subsequent microstructural evolution are well-related to the process parameters, and the properties and characteristics of the as-produced interfaces may be predicted accordingly. The experimental conditions and results of wetting experiments, together with thermodynamic-based models predicting thermophysical property values of liquid Ir-Si alloys, are valuable key input data that are now available for the numerical study of infiltration processes. Full article

Edible coatings are widely used to modulate oil uptake and moisture in fried foods. In this study, we evaluated a microfluid-assisted flow-blurring spray against conventional application by dipping/spraying, focusing on the coating efficiency and preliminary implications for sustainable process. This study combines benchtop experiments with a near-nozzle numerical analysis where the gas–liquid interface and primary breakup are modeled using the Volume of Fluid (VOF) approach implemented in OpenFOAM, configured for a flow-blurring geometry to generate whey protein isolate (WPI) coatings. Viscosity, density, solid content, and contact angle were validated experimentally and used in the simulation setup. An image-based droplet pipeline quantified spray characteristics, yielding a volumetric median diameter D₅₀ = 83.69 µm and confirming process uniformity. Contact angles showed marked substrate dependence: hydrophilic surfaces, 68°–85°; hydrophobic surfaces, 95°–110°. For turkey sausages, sessile-drop contact angles were not determinable (N.D.) due to wicking/roughness; wettability was therefore assessed on smooth surrogates and via performance metrics. Fit-for-purpose simulation procedures are outlined. Microfluidic application (WPI-McF) lowered oil uptake versus uncoated controls. Together, robust modeling, targeted image analytics, and high-precision microfluidics enable rational tuning of coating microstructure and barrier performance, offering a scalable pathway to reduce lipid content and enhance fried food quality. Full article

The evaporation of sessile water drops involves coupled heat and mass transfer and is influenced by temperature, relative humidity, and the nature of the surface on which the drop rests. This work investigates the possibility of using vibration to enhance evaporation kinetics. For this purpose, experiments were conducted with vertical vibration near the resonant frequency. An original experimental device was designed, including a shaker controlled by a signal generator and an amplifier, a high-speed camera, and an adapted lighting system. The amplitude–frequency relationship was first examined to select the resonance frequency. As expected, the evaporation kinetics of two drops—one with vibration at the resonance frequency and the other without vibration—demonstrate that vibration accelerates evaporation and reduces drying time by 20.6% on PTFE substrate and by 23.5% on glass substrate. Full article

To support computational studies and process optimization that require temperature-dependent thermophysical properties, this study characterized the wettability, surface tension, liquid–solid interfacial tension (IFT), and work of adhesion of Al 7075-T6 alloy from 923–1073 K under argon on porous alumina, tungsten, and nonporous alumina substrates using sessile drop experiments and Young’s and Young–Dupre equations, respectively. Furthermore, the substrates’ room-temperature surface free energy (SFE) characteristics were characterized using the Owens–Wendt–Rabel–Kaelble model. The contact angle results revealed the alloy’s poor wettability on all substrates. The surface tension data ranged from 718.87–942.90 mN·m⁻¹ in decreasing order of tungsten, porous alumina, and nonporous alumina. The SFE results of the porous alumina, nonporous alumina, and tungsten substrates were 44.92, 43.32, and 42.03 mN·m⁻¹, respectively. Also, the calculated liquid–solid IFT values ranged from 539.24–835.51 mN·m⁻¹ in decreasing order of porous alumina, tungsten, and nonporous alumina. Additionally, the calculated work of adhesion values ranged from 123.97–479.44 mN·m⁻¹ in decreasing order of nonporous alumina, tungsten, and porous alumina, respectively. Thus, the wettability, surface tension, and liquid–solid IFT of Al 7075-T6 alloy on the substrates were affected by the substrates’ SFE characteristics, thereby affecting the work of adhesion. Full article

The study involved measurements of surface tension of liquid binary copper-titanium alloys with respect to their chemical composition and temperature as well as investigations of the liquid alloy–refractory material-gaseous phase system wettability using usual refractory materials, i.e., graphite, aluminum oxide and magnesium oxide. The experiments were performed with the use of the sessile drop method and a high-temperature microscope coupled with a camera and a computer. The aim of this study was to determine the influence of titanium content in the Cu-Ti alloy on the surface tension and contact angle at the interface between the liquid alloy and the refractory material. The influence of temperature on these parameters was also examined. The tests were carried out for copper-titanium alloys with a maximum content of 1.5% wt. Ti, in the temperature range of 1373 to 1573 K. The test results indicate that as the titanium content in the alloy increases, its surface tension increases slightly. However, an increase in temperature causes a decrease in the surface tension of the alloys. In the case of an alloy containing 1.5% wt. Ti, surface tension at a temperature of 1373 K reaches 1351 mN∙m⁻¹, and at a temperature of 1573 K, it decreases to 1315 mN∙m⁻¹. As the temperature and titanium content in the alloy increase, a decrease in the contact angle is observed. The highest values of contact angles were recorded in the case of contact of the liquid alloy with graphite. For an alloy containing 0.1% wt. Ti at a temperature of 1373 K, the contact angle reaches 132°, while at a temperature of 1573 K, it decreases to 128°. For an alloy containing 1.5% wt. Ti, the values of contact angles are 100° and 96°, respectively. However, the contact angles have the lowest values for magnesium oxide. In the case of a temperature of 1573 K and an alloy containing 1.5% wt. Ti, the contact angle reaches 49°. Such a significant impact of titanium content on the contact angles may be due to its high affinity for oxygen (contact with a substrate made of Al₂O₃ and MgO and its reactivity with carbon (contact with graphite). Full article

The bond strength between basalt fibers and asphalt binders is an important parameter that can be used to evaluate the influence of basalt fibers on the mechanical properties of asphalt binders and asphalt mixtures. To date, however, there remains a lack of methods that can be used to assess the bond strength between basalt fibers and asphalt binders. This study employed a fiber-asphalt pull-out tester (POT). Significant upward, peak, and downward stages were observed from the relationship curves between the pull-out force (POF) and displacement, corresponding to the holding stage and reaching the maximum POF stage and the sliding or failure stage between fibers and asphalt binders. Maximum POF is recommended to calculate the bond strength between basalt fibers and asphalt binders. The types of asphalt binders suitable for basalt fibers and the appropriate fiber embedding depths for different types of asphalt binders guiding the selection of fiber length are recommended based on the influence of fiber embedding depth and asphalt binders on the fiber–asphalt bond strength. In addition, surface energy was used to calculate the bond strength as well. Surface energy was determined from contact angle measurements using the sessile drop method. Furthermore, a scanning electron microscope (SEM) was employed to examine the bond mechanism between asphalt binders and basalt fibers. These experiments showed how basalt fibers serve to reinforce asphalt mixtures by bonding with asphalt binders. Full article

High-temperature wetting of natural, high-purity quartz (SiO₂) and liquid magnesium (Mg) was investigated at temperatures between 973 and 1273 K. Sessile drop experiments using the capillary purification (CP) procedure were carried out under an Ar gas atmosphere (N6.0), eliminating the native oxide layer on the surface of Mg melt. The results showed that the wetting behavior was strongly dependent on temperature. At 973 and 1073 K, the wetting system displayed relatively large contact angles of 90° and 65°, respectively, demonstrating modest wetting. The wetting increased to some extent by increasing the temperature to 1123 K with a wetting angle of 22°. However, the SiO₂/Mg system demonstrated complete wetting at temperatures of 1173 K and above. Furthermore, interface microstructure examination showed different reaction product phases/microstructures, depending on the wetting experiment temperature. Full article

In this study, the surface laser treatment of a new type of dental biomaterial, a Ti-graphite composite, prepared by low-temperature powder metallurgy, was investigated. Different levels of output laser power and the scanning speed of the fiber nanosecond laser with a wavelength of 1064 nm and argon as a shielding gas were used in this experiment. The surface integrity of the machined surfaces was evaluated to identify the potential for the dental implant’s early osseointegration process, including surface roughness parameter documentation by contact and non-contact methods, surface morphology assessment by scanning electron microscopy, and surface wettability estimation using the sessile drop technique. The obtained results showed that the surface roughness parameters attributed to high osseointegration relevance (Rsk, Rku, and Rsm) were not significantly influenced by laser power, and on the other hand, the scanning speed seems to have the most prevalent effect on surface roughness when exhibiting statistical differences in all evaluated profile roughness parameters except Rvk. The obtained laser-modified surfaces were hydrophilic, with a contact angle in the range of 62.3° to 83.2°. Full article

This work focuses on wetting two types of substrates (a platinum substrate and a polished graphite substrate) by molten polycomponent oxide system CaO–MgO–SiO₂–Al₂O₃–B₂O₃ to test the level of interaction at high temperatures. The tested systems were subjected to high-temperature wetting tests in the temperature range from liquidus temperature to 1550 °C using the sessile drop method. A total of four oxide systems were tested with graded boron oxide contents ranging from 0 to 30 wt%. The experiments were conducted in a CLASIC high-temperature resistance observation furnace and an inert atmosphere of high-purity argon. Droplet silhouettes were obtained with a CANON EOS 550D high-resolution camera during heat treatment, with reactive and non-reactive wetting occurring depending on the substrate type. The dependence of the average wetting angles on temperature and time was evaluated, and it was found that boron oxide decreased the average wetting angles of molten oxide droplets. The analyses were accompanied by the SEM/EDX analysis of the substrate and FTIR analysis of the droplets after high-temperature experiments. The phase composition of the oxide systems was evaluated by XRD analysis. Full article

The wetting behavior of liquid magnesium drop on pure tungsten substrates was investigated, for the first time, with the sessile drop method combined with non-contact heating and capillary purification of a Mg drop from a native oxide film. A specially designed apparatus dedicated to the investigation of the high-temperature interaction of dissimilar materials was used. The comparative experiments were performed under isothermal conditions at temperatures of 700 °C and 740 °C using two atmospheres: Ar + 5 wt.% H₂ and pure Ar, respectively. During high-temperature tests for 180 s, the images of the Mg/W couples were recorded with CCD cameras (57 fps) from two directions of observation. The solidified drop/substrate couples were subjected to structural characterization using scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). Under the applied measurement conditions, liquid Mg revealed non-wetting behavior on W substrates (a contact angle θ > 90°). The average value of the contact angle under the flowing Ar atmosphere at 740 °C was θ_av = 115°, whereas it was higher under the flowing Ar + 5 wt.%. H₂ atmosphere at a lower temperature of 700 °C, showing θ_av = 122°. Independently on employed atmosphere and temperature, SEM + EDS analysis of solidified sessile drop couples did not display any new phases and mass transfer between the Mg drop and the W substrate, whereas the presence of discontinuities at the Mg/W interface of cross-sectioned couples were well-distinguished. Non-wetting and a lack of permanent bonding between the Mg drop and W substrates have a good agreement with the Mg–W phase diagram calculated with the help of FactSage software and FTlite database, i.e., the non-reactive nature of the Mg/W couple because W does not dissolve in liquid Mg and it does not form any compounds with Mg. These findings allow for the recommendation of tungsten as a suitable refractory material for long-time contact with liquid Mg in different container-assisted methods of materials characterization as well as in liquid-assisted processing of Mg components. Full article

Fe-26Si-9B alloy was selected as a potential phase change material (PCM) to store energy at temperatures up to 1300 °C. A suitable refractory material is crucial to building a PCM container for Fe-26Si-9B alloy in thermal energy storage systems. The refractory material should have the ability to withstand corrosion from liquid Fe-26Si-9B alloy and should not pollute the alloy after long-term thermal cycles at high temperatures. In this work, Si₃N₄ was selected as a candidate refractory material. To investigate the interaction between Si₃N₄ and Fe-26Si-9B alloy, the wettability property of an Fe-26Si-9B/Si₃N₄ system was examined in a sessile drop furnace at temperatures up to 1350 °C. Moreover, Fe-26Si-9B alloy was subjected to 1–12 thermal cycles at temperatures between 1100 and 1300 °C, where the alloys were placed in Si₃N₄ crucibles in a resistance furnace under argon. According to the experiments, the equilibrium contact angle between the Fe-26Si-9B droplet and Si₃N₄ substrate was measured to be ~143°, which is non-wetting behavior. Microstructural analyses showed that FeSi, FeB, FeSiB₃, and SiB₆ were formed in the solidified Fe-26Si-9B alloy, in which FeSi + FeSiB₃ constituted the eutectic structure. No nitride phases were introduced to the Fe-26Si-9B alloy, and no new interlayer was produced at the interface between the Fe-26Si-9B alloy and Si₃N₄ crucible after the thermal cycle experiments. In addition, the formed phases were stable with the increase in thermal cycles. All the results show that Si₃N₄ refractory material is suitable for Fe-26Si-9B alloy containers at high temperatures. Full article

Ti₂AlC is a typical MAX (M: early transition metal, A: main group element, and X: carbon and/or nitrogen) phase with ceramic and metallic properties due to its unique nano-layered structure. In order to investigate the interaction behavior between Ag and Ti₂AlC, a sessile drop experiment was conducted at 1080 °C for 5 min. The atomic rearrangement occurred at the Ag–Ti₂AlC interface was revealed using high-angle annular dark-field scanning transmission electron microscopy coupled with high-resolution transmission electron microscopy analysis. The results show that Ag nanoclusters generally appeared in most of the Ag–Ti₂AlC interaction regions thermally processed at 1080 °C. In addition, Ag can also substitute for Al and Ti atoms in the Ti₂AlC, promoting local structural decomposition of the Ti₂AlC and producing 4H–Ag with a hexagonal close-packed (hcp) structure. Additionally, Al atoms released from the Ti₂AlC lattices can dissolve locally into the liquid Ag, particularly at the grain boundaries. When the loss concentration of Al exceeded the critical level, the Ti₂AlC started to decompose and the residual Ti₆C octahedrons and Al atoms recombined, giving rise to the production of anti-perovskite Ti₃AlC with a cubic structure. Lastly, the discrepancy in substitution behavior of Ag in the Ti₂AlC was compared when thermally processed at different temperatures (1030 °C and 1080 °C). This work contributes to the understanding of the intrinsic stability of Ti₂AlC MAX ceramics under high-temperature treatment. Full article

The behavior of Mo in contact with molten Al was modelled by classical molecular dynamics (CMD) simulation of a pure Mo solid in contact with molten Al at 1200 K using the Materials Studio^®. Results showed that no reaction or cross diffusion of atoms occurs at the Mo(s)–Al(l) interface, and that molten Al atoms exhibit an epitaxial alignment with the exposed solid Mo crystal morphology. Furthermore, the two phases {Mo(s) and Al(l)} are predicted to interact with weak van der Waals forces and give interfacial energy of about 203 mJ/m². Surface energy measurements by the sessile drop experiment using the van Oss–Chaudhury–Good (VCG) theory established a Mo(s)–Al(l) interface energy equivalent to 54 mJ/m², which supports the weak van der Waals interaction. The corrosion resistance of a high purity (99.97%) Mo block was then tested in a molten alloy of 5% Mg mixed in Al (Al-5 wt.%Mg) at 1123 K for 96 h, using the ALCAN’s standard “immersion” test, and the results are presented. No Mo was found to be dissolved in the molten Al-Mg alloy. However, a 20% mass loss in the Mo block was due to intergranular corrosion scissoring the Mo block in the ALCAN test, but not as a result of the reaction of pure Mo with the molten Al-Mg alloy. It was observed that the Al-Mg alloy did not stick to the Mo block. Full article