Changes In Surface Morphology Research Articles

Effects of surfactant types on anthracite dust wettability: Experimental and molecular simulations

To study the wetting mechanism of surfactants at the solid–liquid interface of anthracite, a combination of experiments and molecular simulation was used to explore the adsorption and wetting processes of four surfactants, namely, fatty alcohol polyoxyethylene ether N = 9 (AEO9), Triton X-100, rapid penetrant T (PRT), and sodium alkyl ether sulfate (AES) on anthracite. The wetting mechanism of surfactants on anthracite was analyzed at both macroscopic and microscopic levels by surface tension, contact angle, settling time, and changes in surface morphology and functional groups on the anthracite surface. The presence of OH-π and C = O was determined to significantly enhance anthracite wettability. The anthracite/surfactant/water system was constructed from a microscopic perspective, and the interaction energies, relative concentration distributions along the Z-axis, diffusion coefficient (D) of water molecules, radial distribution functions (RDF) of hydrophilic groups and water molecules, and coordination numbers of the components were analyzed. The results show that the wetting effect depends on the adsorption state of the surfactant at the anthracite/water interface and the strength of the interaction between the surfactant and water molecules. The addition of surfactants enhances the adsorption thickness of water molecules along the Z-axis and generates more hydrogen bonds, which play a role in fixing water molecules and lead to a decrease in the D of water molecules. RPT forms the highest number of hydrogen bonds with water molecules and has the lowest D of 0.479 × 10-5 cm2/s, indicating strong wetting ability. The RDF of O atoms in surfactants and water molecules shows a similar trend, with two peaks one strong and one weak. The coordination numbers are 1.356, 1.057, 1.003, and 0.903, respectively. The final wettability of the surfactant on the anthracite depends on the synergistic interaction between the oxygen functional groups (OGs) as compared to the coordination number of the individual OGs

Effect of radiotherapy on microhardness and surface morphology of pretreated primary teeth with silver diamine fluoride: an in vitro study

Abstract Background: Children with head and neck cancer undergo radiation therapy, which has proved to be a successful treatment option. One of the common side effect of radiation therapy has been radiation induced caries. This is not as a result of the decreased salivary flow, but rather as a result of the direct impacts of these harmful rays on the enamel of the teeth. Silver diamine fluoride (SDF) is an effective remineralising agent for initial carious lesions and prevents demineralisation of the already deep carious agent. Various studies have also proved its effectiveness in improving the microhardness of the teeth. Hence, the objective of this study was to evaluate whether radiotherapy causes changes in the microhardness and surface morphology of enamel in primary teeth pretreated with SDF. Method: 22 primary teeth samples were divided into two groups with 11 samples in each group. The study group samples were pretreated with SDF and in the control group no pretreatment was done. Both groups were subjected to radiotherapy of 60 Gy radiation for a duration of 30 days. The samples were tested using the Vickers microhardness test and scanning electron microscope (SEM) analysis for surface morphological changes post radiotherapy. Results: It was found that there was a statistically significant difference (p<0.001) in mean microhardness values between the two groups. The mean microhardness of the SDF group (254.07 ± 35.84) was significantly higher that the control group (88.18 ± 6.79). SEM image of enamel of control teeth displayed loss of smooth homogeneous surface and more amorphous structures were seen which was very evident in comparison to the SDF group. Conclusion: Following radiation therapy, SDF application led to greater microhardness of the enamel surface and less morphological alteration in the surface enamel of primary teeth.

Effects of copper and bismuth dopants on PVA/NBT film as an X-ray dosimeter

Low-dose X-rays in the order of milligrays (mGy) are employed in diagnostic radiology. This poses a challenge, considering commercially used dosimeters have limitations in detecting low-dose X-rays. Accordingly, the goal of this research was to fabricate a nitro blue tetrazolium-doped polyvinyl alcohol (PVA/NBT) film dosimeter that could respond to low-dose X-rays while also investigating the effects of introducing copper(II) and bismuth(III) ions on the film's detecting ability. The films were synthesized by the solvent casting method and then exposed to X-ray radiation at doses in the range of 0–2.626 mGy. Optical density and UV–Vis transmittance measurements were carried out to identify changes in the film's optical characteristics brought on by X-ray radiation. In addition, changes in the film's surface morphology and chemical structure were examined by scanning electron microscopy (SEM) and FTIR spectroscopy. According to the results of the optical density measurement, introducing copper(II) ions to the film increased its sensitivity and response linearity. In contrast, the opposite was shown in the case of bismuth(III)-doped films. According to FTIR analysis, film X-ray irradiation caused the PVA to degrade. The development of grain structures on the film surface might be related to the reduction of the copper(II) and bismuth(III) ions. This study discovered that copper(II) ion-doped PVA/NBT film has promising low-dose X-ray detection properties.

Fabrication of Vascular Grafts Using Poly(ε-Caprolactone) and Collagen-Encapsuled ADSCs for Interposition Implantation of Abdominal Aorta in Rhesus Monkeys.

The production of small-diameter artificial vascular grafts continues to encounter numerous challenges, with concerns regarding the degradation rate and endothelialization being particularly critical. In this study, porous PCL scaffolds were prepared, and PCL vascular grafts were fabricated by 3D bioprinting of collagen materials containing adipose-derived mesenchymal stem cells (ADSCs) on the internal wall of the porous PCL scaffold. The PCL vascular grafts were then implanted in the abdominal aorta of Rhesus monkeys for up to 640 days to analyze the degradation of the scaffolds and regeneration of the aorta. Changes in surface morphology, mechanical properties, crystallization property, and molecular weight of porous PCL revealed a similar degradation process of PCL in PBS at pH 7.4 containing Thermomyces lanuginosus lipase and in situ in the abdominal aorta of rhesus monkeys. The contrast of in vitro and in vivo degradation provided valuable reference data for predicting in vivo degradation based on in vitro enzymatic degradation of PCL for further optimization of PCL vascular graft fabrication. Histological analysis through hematoxylin and eosin (HE) staining and fluorescence immunostaining demonstrated that the PCL vascular grafts successfully induced vascular regeneration in the abdominal aorta over the 640-day period. These findings provided valuable insights into the regeneration processes of the implanted vascular grafts. Overall, this study highlights the significant potential of PCL vascular grafts for the regeneration of small-diameter blood vessels.

Understanding the Relationship between Surface Quality and Chip Morphology under Sustainable Cutting Environments.

Although chip morphology changes according to the machining method and related cutting parameters, chip formation affects the quality of the machined surface. In this context, it is very important to understand the relationship between chip morphology and surface quality, especially in materials that are difficult to machine. In the presented study, the changes in chip morphology, surface morphology, and surface quality criteria (Ra and Rz) that occurred during the milling of precipitation-hardened steel in different cutting environments were analyzed. Milling experiments were carried out in dry, MQL (minimum quantity lubrication), nano-MQL (graphene), nano-MQL (hBN), Cryo, and Cryo-MQL environments using TiAlN-coated inserts and three different cutting speeds and feed rates. While the highest values in terms of Ra and Rz were measured in dry machining, the minimum values were obtained in a nano-MQL (hBN) cutting environment. Due to the lubrication and low friction provided by the MQL cutting environment, chips were formed in thinner segmented forms. This formation reduced the chip curve radius and thus provided a more stable surface morphology. On the other hand, Cryo-ambient gas could not effectively leak into the cutting zone due to the intermittent cutting process, but it increased the brittleness of the chips with the cooling effect and provided a similar surface morphology. The values of minimum Ra and Rz were obtained as 0.304 mm and 1.825 mm, respectively, at a 60 m/min cutting speed and 0.04 mm/rev feed. Consequently, the use of nano-MQL cutting medium is seriously recommended in terms of surface quality in milling operations of difficult-to-machine materials.

Wetting Behavior Driven by Surface Morphology Changes Induced by Picosecond Laser Texturing.

The laser surface texturing (LST) technique has recently been used to enhance adhesion bond strength in various coating applications and to create structures with controlled hydrophobic or superhydrophobic surfaces. The texturing processing parameters can be adjusted to tune the surface's polarity, thereby controlling the ratio between the polar and dispersed components of the surface free energy and determining its hydrophobic character. The aim of this work is to systematically select appropriate laser and scan head parameters for high-quality surface topography of metal-based materials. A correlation between texturing parameters and wetting properties was made in view of several technological applications, i.e., for the proper growth of conformal layers onto laser-textured metal surfaces. Surface analyses, carried out by scanning electron microscopy and profilometry, reveal the presence of periodic microchannels decorated with laser-induced periodic surface structures (LIPSS) in the direction parallel to the microchannels. The water contact angle varies widely from about 20° to 100°, depending on the treated material (titanium, nickel, etc.). Nowadays, reducing the wettability transition time from hydrophilicity to hydrophobicity, while also changing environmental conditions, remains a challenge. Therefore, the characteristics of environmental dust and its influence on the properties of the picosecond laser-textured surface (e.g., chemical bonding of samples) have been studied while monitoring ambient conditions.

Enhanced mechanical performance and damping behavior of CFRP composites through exfoliated MWCNT functionalization

In evaluating high-performance multiwall carbon nanotube (MWCNT) based carbon fiber composites, effective chemical functionalization of fillers for sufficient exfoliation and precise interface interactions with resin matrix are challenging to attain due to significant interlayer cohesive energy and inactive surfaces of composites. Herein, we demonstrate an effective way to produce carbon fiber-reinforced polymer (CFRP) composite with amended interfacial characteristics via incorporation of MWCNT through oxidation followed by silane functionalization with their exfoliation levels (0/48/60/72 h). The surface functional elements, morphological changes, elemental groups, quantitative information, and thermal degradation of silane functionalized MWCNTs were characterized by FESEM/HR-TEM, XRD, UV, and TG-DTA analysis, respectively. The influence of silane functionalized MWCNT reinforcement on CFRP's mechanical properties were examined using tensile, flexural, ILSS, and damping behavior was analyzed through impulse excitation technique (IET). The resulting silane-modified MWCNTs with 60 h oxidation (OAC-60) infused CFRP demonstrated significant enhancement in flexural strength (73.8%), tensile strength (58.2%), interlaminar shear strength (28.5%) compared to pure-CFRP.

Effects of photodegradation performance with PLA‐containing samples on double injection molding

AbstractThe influence of different overlay layers (ABS, PC, and PLA) is investigated on the photodegradation behavior of poly(lactic acid) (PLA)‐containing samples in double injection molding, and PLA/PLA samples serve as the control group. In terms of microstructure, an analysis is conducted on the chemical structure, thermal performance, crystallinity, and molecular weight of the base layer of samples. The carbonyl index and molecular weight of the base layer of PLA/PLA samples decrease rapidly, and the trend of crystallinity change is also fast. Among them, the number of molecular chain scissions decreases to 0.61, and the crystallinity increases to a maximum of 17.93%, which indicates that the photodegradation degree of the base layer of PLA/PLA samples is greater than that of the other two samples. The microscopic surface morphology change of the base layer of three PLA‐containing samples is analyzed. The base layer of PLA/PLA samples becomes rougher after 600 h of UV degradation. Meanwhile, compared with other PLA‐containing samples, the percentage of tensile strength loss of PLA/PLA samples is higher, decreasing by 16.64%. In summary, using acrylonitrile butadiene styrene (ABS) and polycarbonate (PC) materials as overlay layers for double injection molding can mitigate the photodegradation of the base layer of PLA‐containing samples in double injection molding.

Observation of dynamic nanoscale thermal expansion in mirrors and graphene-aided heat dissipation by an advanced chromatic confocal microscopy

In this Letter, dynamic nano-thermal expansion images of reflective mirrors from high-intensity incident laser beams were observed in situ. The inspections are based on rapid 3D surface morphology changes on the reflective surfaces, captured by a Chromatic Confocal Microscope with Nanoscale Sensitivity (CCMNS). Nano-expansions of two types of coatings were studied: the E02 dielectric coating (coating 1) and the graphene-on-E02 complex film (coating 2), both applied to the same fused silica substrate. The superior thermal dissipation properties of coating 2, including enhanced heat dissipation, suppressed wavefront distortion, and its unique negative expansion coefficient, were observed. In addition to studying the effects of graphene coating, the CCMNS demonstrates an accurate and efficient approach for evaluating reflective mirrors. Moreover, the proposed methodology possesses enormous potential across various fields, ranging from estimating photonic elements dealing with high-intensity beams to physical thermal conductivity measurements.

Biocompatibility and Cytotoxicity of Pulp-Capping Materials on DPSCs, With Marker mRNA Expressions

ObjectivesThe present study aimed to (i) investigate biocompatibility and cytotoxicity of pulp capping materials on viability of hDPSCs, (ii) determine angiogenic, odontogenic, and osteogenic marker mRNA expressions, and (iii) observe changes in surface morphology of the hDPSCs using SEM. MethodsImpacted third molars were used to isolate the hDPSCs, which were treated with extract release fluids of the pulp capping materials (Harvard BioCal–Cap, NeoPutty MTA, TheraCal LC, and Dycal). Effects of the capping materials on cell viability were assessed using MTS assay and the apoptotic/necrotic cell ratios and ROS levels from a flow cytometry. Marker expressions (ALP, OCN, Col1A, SPARC (ON) and VEGF) were determined by RT-qPCR. Changes in surface morphology of the hDPSCs were visualized by SEM. ResultsThe MTS assay results at days 1, 3, 5 and 7 indicated that Harvard BioCal–Cap, NeoPutty MTA and TheraCal LC did not adversely affect cell viability when compared to the control group. According to the MTS assay results at day 14, no significant difference was found among Dycal, Harvard BioCal–Cap, NeoPutty MTA and TheraCal LC affecting the cell viability. Dycal was the only capping material that increases the ROS level. High levels of VEGF expression were observed in Harvard BioCal-Cap, TheraCal LC, and NeoPutty MTA. NeoPutty MTA and Dycal up-regulated OCN expression, whereas TheraCal LC up-regulated Col1A and SPARC expression. Only Dycal increased ALP expression. The hDPSCs were visualized in characteristic spindle morphology by SEM due to TheraCal LC and Harvard BioCal–Cap. ConclusionsNeoPutty MTA and Harvard BioCal–Cap showed suitable biocompatibility values, and in particular, these pulp capping materials were observed to support the angiogenic marker. Clinical SignificanceSince it was thought that cytotoxicity and biocompatibility values would contribute significantly to future studies, a new pulp capping material, NeoPutty MTA and Harvard BioCal-Cap, were used in this study.

A water stable Cu-MOF/GO composite as a persulfate activator for efficient degradation of dye wastewater

Water pollution caused by textile dyes is considered a major and growing issue. To address this challenge, in this research, water-stable Cu-MOFs/GO composite catalysts were produced using the hydrothermal synthesis method as an efficient persulfate (PDS) activator for methyl orange (MO) degradation. We also explored the changes in surface morphology, crystal structure, surface functional groups, and valence states of the materials before and after the introduction of GO by Cu-MOFs. It was shown that Cu-MOFs/GO demonstrates a more stable surface structure, and the unique folded structure of GO provides a better hydrophobic environment for Cu metal cluster hence making MOF easier to grow. The Cu-MOFs/GO-PDS system showed a high activation performance on persulfate in a wide pH range (3–11), meanwhile, was less affected by the presence of natural anions in the environment and more inhibited by natural organic matter citric acid. Furthermore, the Cu-MOFs/GO had excellent stability, reusability and structural integrity, and the removal rate of MO was maintained after five cycles. In terms of oxidation mechanism, in addition to the generation of ·SO4− and OH· radicals, there were also singlet oxygen 1O2 and active Cu(III) in the system, and all of these active substances contributed to the removal of pollutant MO.

Study on the high temperature performance of recycled concrete with manufactured sand

Recycled concrete with manufactured sand (RCM) is a type of recycled concrete that uses manufactured sand as fine aggregate, and there have been limited reports on the investigation of its high temperature performance in the construction industry. This study, starting from two curing regimes, explored the high temperature performance of RCM with water-to-cementitious ratios of 0.32, 0.4, and 0.48. Various physical properties of the samples in each group were tested, including surface morphology changes, mass loss rate, microstructure and composition alterations, as well as fundamental mechanical properties like compressive strength and elastic moduli. The experimental results indicate that RCM specimens exhibit slightly higher compressive strength after 7 d of high-temperature water curing compared to the 30 d standard curing. Furthermore, following high temperature tests ranging from 200 °C to 800 °C, the strength reduction in the specimens is not significantly pronounced when compared to those subjected to standard curing. Utilizing the measured stress-strain curves and existing constitutive models for high temperature behavior of recycled concrete, this study analyzes the influencing factors affecting the performance of RCM under high temperature conditions. The findings provide theoretical support for the practical engineering application of RCM.

Exploring the efficacy of various essential oils in chitosan‐based composite biopolymer films for food packaging

AbstractTo ensure food and environmental safety, biodegradable packaging materials from various natural polymers are being used to preserve the high quality of foods and to increase their shelf life in addition to environmental safety in terms of biodegradability. However, these natural polymers have some disadvantages in functionality. There are many ways to improve functionality, one such way is the addition of essential oils. Therefore, this research work was done to investigate the effectiveness of four diverse essential oils (EOs), namely, lemon‐grass oil (LGO), tea‐tree oil (TTO), thyme oil (THO), and basil oil (BO) in chitosan‐based composite films. The chitosan as a biopolymer, polyvinyl alcohol (PVA) as a compatibilizer, and four different essential oils@0.3% were blended to form composite food packaging films. These nanofilms had better mechanical strength, elasticity, and film thickness. Thermal stability and change in the weight of chitosan alone and composite films were determined by thermogravimetric analysis (TGA). Scanning electron microscopy (SEM) was used to analyze the change in film surface morphology. The Fourier transform infrared (FTIR) spectrum of the base polymer exhibits characteristic peaks at 3400 cm−1 indicating the occurrence of hydrogen‐bonded OH groups, and peaks at 1500–1600 cm−1 corresponding to the amide II band and CO stretch of the acetyl group. Whereas TGA results confirmed the thermal stability of PVA and EO blended films compared to chitosan alone films. The biodegradability of antimicrobial chitosan‐based films exhibited around 15%–19% percentage of degradation in PVA blended films whereas chitosan alone degraded up to 32% after 30 days. Water vapor transmission was high in chitosan alone film (1.9%) and 0.25% in PVA/EO blended films displaying enhancement in hydrophobic qualities of the developed films due to change in hydrophobicity by EO addition. The chitosan and PVA alone films were transparent whereas EO blended films exhibited yellow coloration and became less transparent due to the oil droplets dispersion in films. The shelf life of tomato, bread, and paneer was better in lemongrass and tea tree oil‐incorporated films during storage.

Space-weathering induced changes in hydrated silicates: A multi-scale study combining visible/infrared spectroscopy and electron microscopy

Investigating the effects of space-weathering on primitive bodies is paramount in assessing their composition and understanding their history. For this purpose, we conducted 40 keV He and Ar ion-implantation experiments on terrestrial phyllosilicates, the main components of primitive C-class asteroids: two serpentines, and one saponite. We emulated the effects of the solar wind component of space weathering on hydrated surfaces over timescales of 1E3–4 years in the inner solar system. Spectral changes (from 0.35 to 30 μm in wavelength), surface topography variations, and elemental and morphological changes were investigated. In the visible range, we saw darkening for all samples, accompanied by reddening for the serpentine samples and blueing for the saponite. Spectroscopic features such as the silicate stretching and bending modes at 10 and 20 μm respectively, as well as the (M)-OH bending mode at 16 μm, exhibited a peak shift towards longer wavelength (red-shift), band area decrease, and band widening. The surface of Ar-implanted samples appeared polished, while no difference was noticeable for He-implanted samples. Morphological changes in the ion-implanted layers of our samples include abundant vesiculation and lattice amorphization. Mg and O appear to be particularly mobile upon ion implantation. In particular, dehydroxylation was observed for all samples. Changes observed for spectroscopic features do not correlate systematically with variations of the Mg/Fe ratio. They do correlate with oxygen loss via dehydroxylation and crystal lattice disordering and amorphization. Spectral changes in the visible range and for 10 and 20 μm features appear to be mainly due to crystal amorphization. Variation of the hydration feature at 16 μm correlates with both dehydroxylation and lattice amorphization. Compositional variations affect the hydration feature at 2.7 μm more consistently. The effects detected upon ion implantation on the samples in this work support the identification of spectral trends from the remote-sensing data of primitive bodies Ryugu and Bennu as changes induced by space-weathering. Findings are also compatible with laboratory analysis on returned weathered grains from Ryugu.

Surface Roughness Evaluation of Pre- Versus Post-Crystallization Polish of Two High-Strength Silicate Ceramics for Chairside CAD/CAM Technology

This in vitro study evaluated the surface roughness (Sa) of two high-strength silicate ceramics, lithium disilicate IPS e.max CAD, Ivoclar Vivadent (LDS group), and zirconia-reinforced lithium silicate Vita Suprinity, VITA Zahnfabrik (ZLS group). The surface roughness was investigated before and after milling using different polishing systems and timings relative to the final crystallization of the ceramics. Forty-eight samples per group were polished by a single calibrated operator using two polishing systems: Dialite LD (Brasseler) and Lithium Silicate Polishers (Meisinger) for the LDS group and Dialite LD (Brasseler) and Vita Suprinity Polishing Set Technical (VITA Zahnfabrik) for the ZLS group, both pre- and post-crystallization. Surface roughness was measured using a confocal laser microscope (OLS4000 LEXT/Olympus), with scanning electron microscopy (SEM) used to evaluate surface morphological changes. Significant differences in Sa values were found between baseline groups, with ZLS exhibiting lower values. All polishing methods significantly reduced surface roughness compared to baseline (p ≤ 0.05). No significant differences were found in LDS samples when polishing pre- or post-crystallization (p = 0.129), while for ZLS samples, post-crystallization polishing achieved significantly smoother surfaces (p < 0.001). The study concluded that the choice of polishing system and timing did not significantly affect surface roughness for LDS. However, it is recommended that post-crystallization polishing be performed for the optimal smoothness of ZLS. This study aimed to evaluate the post-milling polishing procedures of CAD/CAM high-strength restorations, emphasizing the importance of an optimal surface roughness to prevent issues such as increased risk of abrasion on opposing teeth, enhanced plaque adhesion, and mechanical failures. Investigating these polishing techniques enables clinicians to optimize clinical performance, thereby improving the quality and longevity of high-strength silicate ceramics.

In-situ polymerization of polythiophene/silicon carbide nanocomposites for gas sensing and optoelectronic devices

Silicon carbide (SiC)-reinforced polythiophene (PTh) nanocomposites were synthesized by oxidative in-situ polymerization. The successful inclusion of SiC nanoparticles into the PTh was confirmed by the characteristic peak of Si–C bond around 865 cm−1 in the Fourier transform infrared (FT-IR) spectra. The X-ray diffraction (XRD) patterns demonstrate that the amorphous nature of PTh reduces with the addition of SiC. The intensity of UV–Vis absorbance increased proportionally with filler loading, indicating improved optical properties for PThSiC7 (polythiophene/silicon carbide 7 wt%) nanocomposite compared to pristine PTh. Field emission scanning electron microscopy (FE-SEM) images illustrate the changes in surface morphology of PTh with the addition of SiC and uniform dispersion was observed in PThSiC7. The formation of spherical-shaped moieties was confirmed using transmission electron microscopy (TEM). The shifts in degradation and glass transition temperatures towards higher values were attributed to the enhanced thermal properties of the nanocomposites. Temperature-dependent studies on the electrical and dielectric properties of the samples underscored the excellent conductivity exhibited by PThSiC7 (7 × 10−3 S/cm) with a low activation energy of 0.058 eV. In response to the growing demand for gas sensors, samples were tested to sense ammonia gas, demonstrating that PThSiC nanocomposites were more sensitive than PTh. The controllable optical properties, thermal stability, electrical characteristics, and gas sensing performance of the PThSiC nanocomposites suggest their potential as a promising material for the development of advanced energy storage systems, sensors, and optoelectronic devices.

Co-deposition of natural particles in the acidic zinc electroplating process

The co-deposition of natural particles was studied in zinc electroplating on mild steel in the acidic sulfate bath aiming a composite coating. Despite most papers reported the effect of natural extracts in such process, the evaluation of natural particles adhered to the coating was not explored yet. The process efficiency, surface morphological changes, and corrosion resistance were evaluated in different concentrations of avocado seed powder (ASP, Persea americana), cocoa bean shell powder (CBSP, Theobroma cacao), and garlic peel powder (GPP, Allium sativum). In general, the current efficiency was not significantly influenced by the presence of any natural particles, reaching values over 90 %. The presence of natural particles impacted the active sites on the substrate surface, modifying the grain growth assessed by scanning electron microscopy (SEM) analysis. The GPP samples showed better visual aspect and higher compactivity. By Fourier transform infrared spectroscopy analysis, such natural particles are constituted by molecules of long carbon chains with chemical groups – amines, carboxylic acids, and phenols. Hence, the presence of natural particles in the coating layer led to different responses in the contact angle test, where GPP samples showed higher wettability (θ < 90°), followed by ASP and CBSP samples (θ > 100°). Such behavior indicates a greater bath penetration during the electroplating process in the presence of more hydrophilic particles, which may have resulted in the refined deposits of the GPP samples. The concentration of 0.330 g/L GPP presented higher impedance modulus (6548.3 Ω.cm2 at 0.03 Hz) in the electrochemical impedance spectroscopy (EIE) and reduced the anodic ionic current density at least four times in the scanning vibrating electrode technique (SVET). The same was observed in the salt spray test (SST) adapting ASTM B117, which revealed to be sensitive enough to indicate that the 0.330 g/L GPP sample showed greater corrosion resistance.

Research on the Process of Laser Cladding Ni60 Coating on High-Nickel Cast Iron Surfaces

In order to achieve high-performance coatings on the surface of electric submersible pump impellers, it is crucial to optimize the laser cladding process parameters. Using Ansys 2021 R1 commercial software, a numerical simulation of laser cladding Ni60 powder on high nickel cast iron was conducted. The simulation utilized a 3D Gaussian heat source, parametric language, and life–death unit technology to replicate the characteristics of synchronous powder delivery laser cladding. The study focused on analyzing the temperature field cloud map and molten pool size under different laser power and scanning speeds, narrowing down the process parameter window, selecting optimized laser power and scanning speed, and assessing the changes in surface morphology, melting height and width, dilution rate, microhardness, and microstructure of the laser cladding coating. Results indicate that the coating width and thickness increase with higher laser power and lower scanning speeds. The microstructure consists primarily of dendritic, block, short rod, and long strip formations, and exhibits a tightly distributed and uniform grain structure. Furthermore, the microhardness of the coating shows a negative correlation with laser power and scanning speed. The optimal process parameters were determined to be a laser power of 1100 W and a scanning speed of 6 mm/s. A comparison with the simulation confirmed the effectiveness of the simulation in effectively guiding actual production.

A high-sensitive anisotropic magnetoresistive sensor based on hybrid Ta/NiFe/Ta/Al multilayer structure

High sensitivity is crucial for anisotropic magnetoresistive (AMR) sensors in industrial applications. In this paper, a high- sensitive AMR sensor based on magnetoresistive thin films with Ta/NiFe/Ta/Al four-layer structure is proposed and fabricated. Firstly, the structural parameters were optimized by finite element analysis. Secondly, thin film samples and AMR sensors were prepared. Through the analysis and characterization of reluctance change rate, hysteresis loop, x-ray diffraction and surface morphology and structure, the process parameters were optimized. Finally, the sensor was connected to the designed external circuit, and its technical parameters were tested in a magnetic field test system. The results show that the prepared AMR sensor performs well. It has a high sensitivity of 1.27 mV/V/Oe, a low bridge offset voltage of ±1.64 mV V−1, and a low temperature coefficient of sensitivity of −0.102%/°C. The results contribute to the future development of AMR magnetic field sensor chips.

Mechanism of self-recovery of hydrophobicity after surface damage of lotus leaf

The surfaces of lotus leaves with micro- and nano-waxy cuticle structures are superhydrophobic and possess a self-healing ability to regain hydrophobicity after damage. Inspired by this phenomenon, the problem of water-repellent coatings used in natural environments failing to perform after damage can be solved if these coatings are endowed with rapid self-repair and self-growth functions. However, there has been almost no exploration into the hydrophobicity self-repair process in lotus leaves. The changes in surface morphology during the hydrophobicity recovery process are not understood. There is a lack of research on the hydrophobicity recovery in lotus leaves. In this study, the damage and recovery experiments on lotus leaf surfaces were carried out in an artificial climate chamber, and the water repellency recovery process and typical water repellency roughness parameters regained time were obtained. Upon analyzing the differences in the recovery process of different damage types, the recovery mechanism after lotus leaf surface damage was obtained. Finally, it was found that the microscopic roughness determined the static contact angle (WCA) of the lotus leaf surface, and the nanoscopic roughness determined the rolling angle (SA). The dual factors of the recovery of the extruded epidermal tissue and the regeneration of the epidermal wax crystals determined the hydrophobicity recovery process in damaged lotus leaves.