Surface Morphology Characteristics Research Articles

Inverse Identification of Constituent Elastic Parameters of Ceramic Matrix Composites Based on Macro–Micro Combined Finite Element Model

Accurate material performance parameters are the prerequisite for conducting composite material structural analysis and design. However, the complex multiscale structure of ceramic matrix composites (CMCs) makes it extremely difficult to accurately obtain their mechanical performance parameters. To address this issue, a CMC micro-scale constituents (fiber bundles and matrix) elastic parameter inversion method was proposed based on the integration of macro–micro finite element models. This model was established based on the μCT scan data of a plain-woven CMC tensile specimen using the chemical vapor infiltration (CVI) process, which could reflect the real microstructure and surface morphology characteristics of the material. A BP neural network was used to predict the multiscale stiffness, considering the influence of the porous structure on the macroscopic stiffness of the material. The inversion process of the constituent elastic parameters was established using the trust-region algorithm combined with an improved error function. The inversion results showed that this method could accurately invert the CMC constituent elastic parameters with excellent robustness and anti-noise performance. Under four different degrees of deviation in the initial iteration conditions, the inversion error of all parameters was within 1%, and the maximum inversion error was only 2.16% under a 10% high noise level.

Crack Development and Electrical Degradation in Chromium Thin Films Under Tensile Stress on PET Substrates

The mechanical and electrical deterioration of chromium (Cr) thin films sputtered onto polyethylene terephthalate (PET) substrates under tensile strain was studied. Understanding mechanical and electrical stability due to imposed strain is particularly important for device reliability, as the demand for flexible electronic devices increases. Cr thin films, widely spread across the field of electronic and sensor applications, face crack propagation with electrical degradation with tensile stress that can seriously compromise the performance. Accordingly, this study offers new findings on how Cr film thickness might influence crack formation and electrical resistance differently and also the general guidelines for flexible electronic component design with respect to long-term durability. Electrical resistances were measured while mechanically stretching 100- and 200 nm thin sheets. The study focused on crack development and propagation mechanisms in both film thicknesses and their effects on percentage change in electrical resistance (PCER). Scanning electronic microscopy (SEM) was used to characterize surface morphology and observe cracks as the strain rose. Early crack formation in 100 nm Cr films led to rapid PCER increases due to quick crack propagation and fast electrical degradation. Thicker 200 nm films, however, showed a more gradual PCER rise with fewer but deeper cracks, indicating a regulated strain response. Unlike the sharp PCER spike in 100 nm films, 200 nm samples were more variable, with three out of four showing a slight PCER decrease at the end, hinting at partial crack repair or conductive realignment before full failure. These results underscore the role of layer thickness in managing crack propagation and electrical stability, relevant for flexible electronics and strain sensors. This paper is aligned with the ninth goal of the United Nations Sustainable Development Goals, specifically Target 9.5: Enhance Research and Upgrade Industrial Technologies.

Micromechanical properties and fractal homogenization of coal based on nanoindentation

Distinct from hard rock, coal is relatively soft and fragmented. It is not only challenging to prepare test coal samples that meet the requirements of standard mechanical experiments but also impossible to recycle them for repeated testing. There is an urgent need to explore new mechanical testing methods to enhance the study of the mechanical properties of coal. In this study, the micromechanical parameters of the coal matrix solid phase were acquired through targeted nanoindentation technology. The elemental composition, surface morphology, and pore structure characteristics of each indentation point were determined by energy dispersive spectrometer, optical microscope observation, and high-pressure mercury injection experiments. The fractal homogenization equation is deduced based on fractal geometry and the Mori–Tanaka method. The validity of the fractal homogenization approach is verified by integrating the micromechanical parameters and pore structure characteristics of coal, and the impact of the microstructural parameters on the macroscopic mechanical properties of coal is discussed. The results show that the proportion of clay minerals in the solid phase of the coal is the greatest (81.18%), with the main mineral components being kaolinite and illite. The elastic modulus is 1.974 ± 1.036 GPa, the hardness is 0.131 ± 0.108 GPa, and the ratio of upper and lower pore scales conforms to the fractal calibration rate. The macroscopic equivalent elastic modulus rises along with the increase in the fractal dimension. When the fractal dimension is constant, the macroscopic equivalent elastic modulus decreases with the increase in λmin/λmax and increases with the increase in solid phase elastic modulus.

Fabrication of lead halide perovskite solar cells with improved photovoltaic performance using MoSe2 additive strategies

Herein, we reported the fabrication of methyl ammonium lead iodide (MAPbI3) based perovskite solar cells (PSCs). Molybdenum diselenide (MoSe2) was hydrothermally prepared and used as an additive to control the rapid crystallization of MAPbI3. Different weight percentage of (0.1, 0.2, 0.3, 0.4, 0.5 and 0.7%) of the MoSe2 additive was explored to control the crystallization process and improve the surface morphological characteristics of the MAPbI3. The obtained results showed that 0.5% MoSe2 additive modified MAPbI3 based PSCs device demonstrated excellent efficiency of 15.1% with open circuit voltage (Voc) = 0.99 V, photocurrent-density (Jsc) = 21.26 mA/cm2 and fill factor (FF) = 0.72. The fabricated device with 0.5% MoSe2 additive retained more than 85% efficiency whereas pristine MAPbI3 based device retained 49.56% efficiency after 1200 h. This suggested that 0.5% MoSe2 additive modified MAPbI3 based PSCs device has excellent stability compared to the pristine MAPbI3 based PSCs device.

Polymer Composite Coatings Enhanced with Superhydrophobic Properties for Flexible Electronics Applications: A Review

ABSTRACT Flexible electronics have revolutionized various industries by offering lightweight and conformable solutions for diverse applications. However, their vulnerability to environmental factors, particularly moisture, remains a critical challenge. Polymer composite coatings enriched with superhydrophobic properties have gained considerable attention as a promising solution to safeguard flexible electronics. The present research report is a comprehensive review of the recent advancements in the development and application of superhydrophobic polymer composite coatings in flexible electronics, highlighting its potential applications in sensors and EMI shielding. The improvement in superhydrophobic characteristics hinges upon the choice of materials, fabrication techniques, surface morphology, and topographical features. This review article elaborates on the selection criteria for various organic and inorganic fillers suitable for polymers possessing innate hydrophobic or conducting properties. The different materials used as fillers in polymer matrix for fabricating superhydrophobic coating, the factors affecting the superhydrophobic properties of surfaces, and the superhydrophobic properties of fabricated surfaces using different materials have been reported.

Enriched photocatalytic degradation of methylene orange dye using carbon quantum dots surface-decorated TiO2 nanocomposites

Complex molecules in methylene orange (MO) dye-contaminated water are carcinogenic and mutagenic risks to human health. Carbon quantum dot surface-decorated titanium dioxide nanocomposites (CQD-TiO2 NCs) were synthesized via a sustainable hydrothermal method at concentrations of 1.5–3 mL. These NCs exhibits superior electron transfer, light harvesting capabilities, high stability, easy modification, optical characteristics, and photocatalytic properties. The surface morphology, porosity, physiochemical, and optical features of these CQD-TiO2 NCs were characterized using TEM, UV–Vis, PL, BET, BJH micromeritics, pHzpc, and photoelectrochemical measurements. The prepared NCs were evaluated against the photocatalytic degradation of MO dye molecules using a solar simulator system. The TEM revealed ultra-sensitive and tiny CQD materials with graphite phases ranging from 5 to 10 nm and attached to the octahedron surface of TiO2 NCs. The PL analysis observed three distinct emission peaks in the visible region, attributed to the near band edge, interstitial (Tii), and oxygen vacancy (V0). The BET and BJH analyses were conducted to determine the N2 adsorption-desorption surface area and mesoporous structure with pore sizes ranging from 2 to 50 nm. These NCs showed excellent photocatalytic performance, effectively degrading MO up to 99.00 % in a 3 mL variation, indicating that they could be a great candidate for photocatalytic purification of wastewater containing MO dyes.

Characterisation of surface morphology of high voltage DC relay contacts under arc erosion

Abstract High voltage DC relays are a crucial component in new energy vehicles. Due to the high failure rate caused by contact sticking (fusion welding), existing technologies can only analyze contact morphology after failure. There is an urgent need to determine the quantitative characterization value of contact surface morphology and the correlation between morphology, failure mechanisms, and working conditions. In this study, an Olympus DSX1000 microscope is used to extract surface topography data, and a quantitative topography characterization method based on a machine vision system is proposed to quantitatively analyze contact surface changes after arc erosion. Grey correlation analysis was applied to explore the relationship between electrical parameters such as voltage, current, and capacitance, and the contact morphology features. The results show that current and capacitance have the greatest influence on contact surface features after arc erosion, while voltage has a relatively smaller influence. This conclusion is consistent with the experimentally observed arc erosion features. Finally, an arc ion sputtering deposition model was developed to analyze the material transfer mode and its influence on the contact failure mechanism. The results provide a scientific basis for the analysis and design improvement of high voltage DC relays.

Study of the surface features of palladium-based alloys using atomic force microscopy and magnetic force microscopy

The surface state of palladium-based alloys, specifically Pd–6.0In–0.5Ru and Pd–7.0Y (the element content is given in wt.%) has been studied using magnetic force microscopy (MFM) and atomic force microscopy (AFM). The study was conducted within the framework of the current trend to enhance the safety of hydrogen separation and storage. The samples for the study were made of high-purity metals through arc alloying. They underwent reversible hydrogen alloying to investigate the impact of internal deformation of metal systems on their structure-sensitive properties. The study demonstrates the characteristics of the sample surface morphology and domain structure before and after hydrogenation. The local magnetic properties of alloy surfaces have been clarified, and their changes as a result of hydrogen exposure have been identified.

Optimizing Ammonia Detection with a Polyaniline-Magnesia Nano Composite.

Polyaniline-magnesia (PANI/MgO) composites with a fibrous nanostructure were synthesized via in situ oxidative polymerization, enabling uniform MgO integration into the polyaniline matrix. These composites were characterized using FTIR spectroscopy to analyze intermolecular bonding, XRD to assess crystallographic structure and phase purity, and SEM to examine surface morphology and topological features. The resulting PANI/MgO nanofibers were utilized to develop ammonia (NH3) gas-sensing probes with evaluations conducted at room temperature. The study addresses the critical challenge of achieving high sensitivity and selectivity in ammonia detection at low concentrations, which is a problem that persists in many existing sensor technologies. The nanofibers demonstrated high selectivity and optimal sensitivity for ammonia detection, which was attributed to the synergistic effects between the polyaniline and MgO that enhance gas adsorption. Furthermore, the study revealed that the MgO content critically influences both the morphology and the sensing performance, with higher MgO concentrations improving sensor response. This work underscores the potential of PANI/MgO composites as efficient and selective ammonia sensors, highlighting the importance of MgO content in optimizing material properties for gas-sensing applications.

Synthesize and Investigate Structural, Surface Morphology, Optical, and Electrical Characterization of Cu2Se Thin Films by Thermal Evaporation Technique

Synthesize and Investigate Structural, Surface Morphology, Optical, and Electrical Characterization of Cu2Se Thin Films by Thermal Evaporation Technique

Comprehensive Study on the Corrosion Inhibition of Aluminum in HCl by N1, N1'-(Ethane-1,2-diyl)di(ethane-1,2-diamine): Experimental and Theoretical Approaches

The inhibitory effects of the novel molecule N1, N1'-(ethane-1,2-diyl)di(ethane-1,2-diamine) (TETA) on aluminum (Al) corrosion were investigated in 0.2, 0.3, and 0.4 M HCl solutions. Electrochemical impedance spectroscopy (EIS), potentiodynamic polarisation (PDP), quantitative techniques, and surface morphology characterisation were utilised. Surface morphology characterisation via atomic force microscopy (AFM) and scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDS) confirmed the efficacy of the inhibitor in preventing corrosion. Weight loss research revealed that the protective efficacy of TETA grows with increasing concentration but shrinks with increasing temperature of the acidic solution. The findings indicate a marked increase in inhibition efficiency as TETA content rises, reaching 99.0 % when measured by the weight loss method, 98.34% through EIS, and 94.13% via electrochemical polarization. Polarization curves show that TETA stops hydrochloric acid from acting on the anodic type. Both the charge-transfer resistance and the double-layer capacitance decrease with increasing inhibitor concentration, as shown by the adsorption mechanism and supported by the EIS results. "The Langmuir isotherm and negative Gibb's free energy values demonstrate that the inhibitor molecules cling to the metal and that they adsorb to the aluminium spontaneously. In addition to analysing TETA via density functional theory (DFT), the adsorption of TETA on the surface of aluminium (Al) was examined via molecular dynamics (MD) simulations. The results show that the TETA molecule successfully blocks the corrosion process.

Sonication-assisted Activation of Empty Fruit Bunches to Produce Activated Carbon for Supercapacitor’s Electrodes: Surface Chemistry and Morphology Characterization.

Thermochemical treatment of empty fruit bunches (EFBs) had been proven to be the fastest way of converting this agro-industrial waste into value. Two-step carbonization and activation was used to convert the EFB to activated carbon with high specific surface area (SSA) and porosity. Hydrothermal carbonization was done at 225 to 275 ; at retention time of 1 to 3 h. Activation was done at 800 for 1 h, using KOH at two different concentrations. The BET surface area, porosity and surface functional groups of the activated carbon were investigated. The samples experienced change in colourations, with the degree of colouration increases with the time and temperature of the reaction. The increase in these parameters also led to increase in the alkane functional groups and corresponding decreased in the hydroxyl functional groups. The specific surface area was measured using BET and maximum surface of 1375.26 m2/g was obtained when the biomass was carbonized at 275 for 1 h, and activated at 800 using KOH at a concentration of 1:1 to the hydrochar. Ultrasonic post-treatment of the activated carbon enhanced the BET surface area and pore volume to about 1.13 and 1.16 times, respectively. The corresponding pore diameter and volume at this optimum condition were 3.32 nm and 0.73 cm3/g, respectively. The material demonstrated a high specific surface area for electronic and ionic diffusions.

Plasmonic effect of gold nanoparticles on rear side of flexible black silicon wafer fabricated by aluminum-assisted chemical etching

In this work, we investigate the effects of the different sizes of gold (Au) plasmonic nanoparticles (NPs) on the rear surface of flexible black silicon (b-Si) wafer. The flexible b-Si (65 μm thickness) is fabricated by aluminum-assisted chemical etching (AACE) process, utilizing aluminum (Al) as the catalyst. After the b-Si fabrication, nanopores are produced on the flexible wafer surface. Then, gold nanoparticles (Au NPs) are spin-coated on the rear side of the flexible b-Si, followed by surface morphological and optical characterizations. The Au NPs with sizes of 24–92 nm have been deposited on the rear surface of the b-Si wafer. Based on the optical characterization, light absorbance increases above wavelength 800 nm due to enhanced light scattering by the Au NPs at the back surface. The average reflectance (Rave) is calculated in the 300 nm–1100 nm wavelength range for flexible crystalline silicon (c-Si) reference and compared with flexible b-Si surface and flexible b-Si/Au NPs. The lowest Rave of 15.4% is achieved for Au NPs with average size of 92 nm.

Preparation of Stainless Steel Superhydrophobic Surface and Analysis of Hydrophobic Mechanism.

By analyzing the application conditions of hydrothermal oxidation equipment, we found that the corrosion resistance of stainless steel is crucial. It is necessary to prepare superhydrophobic surface to improve the corrosion resistance and find a cost-effective and environmentally friendly preparation method. Therefore, this paper proposes a method combining nanosecond laser and post-treatment, which uses nanosecond laser to etch microstructure and reduces the surface energy through diverse post-treatment methods to achieve hydrophobicity. The surface morphology characteristics were studied, the wettability of various post-treatment methods was compared, and the hydrophobic mechanism was analyzed. The results show that the groove width has a significant impact on the surface morphology. Superhydrophobic surface can be obtained immediately after heat treatment and fluorosilane modification, while natural storage requires more than one month. All of the post-treatment can obtain hydrophobicity by reducing the surface energy, but the chemical composition is distinct. The cost-effective composite process of laser and heat treatment plays a guiding role in future research on the preparation of stainless steel superhydrophobic surface and has broad prospects in the future in large-scale production and application.

Optimizing the Die-Sink EDM Machinability of AISI 316L Using Ti-6Al-4V-SiCp Electrodes: A Computational Approach

Die-sink electric discharge machining (EDM) is essential for shaping complex geometries in hard-to-machine materials. This study aimed to optimize key input parameters, such as the discharge current, gap voltage, pulse-on time, and pulse-off time, to enhance the EDM performance by maximizing the material removal rate while minimizing the surface roughness, residual stress, microhardness, and recast layer thickness. AISI 316L stainless steel was chosen due to its industrial relevance and machining challenges, while a Ti-6Al-4V-SiCp composite electrode was selected for its thermal resistance and low wear. Using Taguchi’s L27 orthogonal array, this study minimized the trial numbers, with analysis of the variance-quantifying parameter contributions. The results showed a maximum material removal rate of 0.405 g/min and minimal values for the surface roughness (1.95 µm), residual stress (1063.74 MPa), microhardness (244.8 Hv), and recast layer thickness (0.47 µm). A second-order model, developed through a response surface methodology, and a feed-forward artificial neural network enhanced the prediction accuracy. Multi-response optimization using desirability function analysis yielded an optimal set of conditions: discharge current of 5.78 amperes, gap voltage of 90 volts, pulse-on time of 100 microseconds, and pulse-off time of 15 microseconds. This setup achieved a material removal rate of 0.13 g/min, with reduced surface roughness (2.46 µm), residual stress (1518.46 MPa), microhardness (259.01 Hv), and recast layer thickness (0.87 µm). Scanning electron microscopy further analyzed the surface morphology and recast layer characteristics, providing insights into the material behavior under EDM. These findings enhance the understanding and optimization of the EDM processes for challenging materials, offering valuable guidance for future research and industrial use.

A mechanism study of thermal resistance formation and post-fire strength recovery in cement paste with carbon nanotubes and nanosilica via focused ion beam/scanning electron microscopy tomography

Although carbon nanotubes (CNT) and nanosilica (NS) have shown substantial potential for enhancing the thermal resistance and post-fire mechanical recovery of cementitious composites, their combined synergistic effects remain unclear. This study aimed to elucidate the influence of CNT and NS double-hybrids on the physicochemical properties of cementitious composites under different heating temperatures (200, 500, and 800 °C) and re-curing conditions (25 °C/65 % RH and water immersion). We assessed the changes in the compressive and tensile strengths, bulk density, surface morphology, hydration products, and pore characteristics using focused ion beam scanning electron microscopy to visualize the evolving nanoscale pore structures. Our findings reveal a remarkable synergistic effect on the thermal resistance and strength recovery properties of the CNT/NS hybrid samples, owing to the stable matrix observed after heating to 800 °C. Following exposure to 800 °C, the tensile strength exhibited a remarkable 69.6 % increase compared to its pre-heating state, without any indication of crack formation. The CNT served as nucleation sites, expediting the pozzolanic reaction of NS during heating and resulting in a homogenized pore structure with interconnected hydrates. The CNT/NS hybrid samples exhibited uniform shrinkage of hydrates without creating nanoscale rod-like pores typical in ordinary cement paste, while the increase in pore volume was predominantly attributed to the expansion of existing pores and the formation of nearby new pores.

Green synthesis of undoped and Ag-doped NiO nanoparticles: Evaluation and their synergetic effect on antimicrobial, anticancer, and antioxidant activities

In this investigation, we successfully synthesized nickel oxide nanoparticles (NiO NPs) using a combustion method with Acacia nilotica gum as a biofuel, and systematically altered silver (Ag) concentrations within the NiO matrix. Post-calcination at 400 °C, various characterization techniques confirmed the formation, surface morphology, and crystalline characteristics of NiO NPs. The Ag-doped NiO NPs, particularly the NiAg4 sample, demonstrated remarkable antimicrobial efficacy, with superior activity against both fungal and bacterial pathogens. The NiAg4 sample also exhibited potent cytotoxicity against HT-29 human colon cancer cells, achieving an IC50 value of 1.5 mg/mL. Toxicological assessments revealed that both undoped and Ag-doped NiO NPs maintained biocompatibility with human red blood cells, indicating their potential for biomedical applications. Additionally, the NPs showed strong antioxidant activity and protein kinase inhibition, further supporting their therapeutic potential. These findings suggest that Ag-doped NiO NPs synthesized through a green protocol possess enhanced bioactivities, making them promising candidates for future in vivo studies and diverse biomedical applications.

Experimental study of abrasive water jet drilling parameters on UHMWPE for biomedical implant applications

ABSTRACT This study addresses this issue by exploring the effectiveness of abrasive water jet drilling (AWJD) as an unconventional machining approach for UHMWPE. The research employs a full factorial analysis to examine various hole characteristics, including machining time (MT), surface roughness (Ra), taper angle (TA), material removal rate (MRR), and taper ratio (TR). The study aims to understand the effect of the process features, namely abrasive water jet pressures (p), traverse rates (v), and abrasive mass flow rates (ma), on the geometry and position of the drilled holes. The results show that (v) and (p) affect the drilled hole characteristics of surface morphology, roughness, MT, MRR, TA, and TR. The microstructural characteristics of the drilled-hole surfaces are analyzed by scanning electron microscopy (SEM). It revealed that the smooth surface is attained at the lower v of 150 mm/min and ma of 250 g/min.

Optimising surface morphology for enhanced radiative properties in thermal energy-efficient materials

Environmental concerns related to heat-absorbing materials in the construction industry can be effectively addressed by optimising the reflectivity of incoming sunlight and thermal emissivity of materials. These radiative properties are closely tied to the surface morphology characteristics of building materials, making superficial topography a critical factor in determining their thermal and energy performance. In our research, we performed reflectance analysis in the UV-Vis-NIR-MIR region and conducted FT-IR analysis to assess the colour and reflectance behaviour of the samples, along with surface morphology and topography investigations. The data collected were utilised in a statistical study to analyse the relationship between superficial topography and thermo-optical characteristics. Our findings underscore the significant impact of surface morphology as a secondary factor influencing radiative properties. Specifically, our results indicate that large-scale components influence mid-infrared absorbance, while surface roughness is crucial in determining solar reflectance properties. Notably, an increase in roughness consistently leads to a reduction in near-infrared and visible reflectance properties by up to 17% and 8%, respectively, with no noticeable effect in the UV region. In conclusion, our research demonstrates the potential for customising and optimising surface properties to reduce energy consumption for cooling purposes and alleviate the urban heat island effect.

Study on the regulation of droplet motion behavior on superhydrophobic surfaces

Wettability properties of the surface is essential for controlling the dynamic sliding of droplets, thereby facilitating surface self-cleaning and drag reduction. This study makes use of chemical etching and surface modification techniques to prepare superhydrophobic surfaces with micro-nano pore structures on copper. This research examines and evaluates the chemical composition, surface morphology, and hydrophobic characteristics of superhydrophobic surfaces, also investigates the exhibited excellent superhydrophobic properties, a positive correlation observed between the concentration of the modifier solution and the surface’s hydrophobic strength. Droplets move in an accelerated fashion on superhydrophobic surfaces, and the total resistance to droplet sliding decreases as the surface hydrophobicity increases and the wall tilt angle decreases. During the motion of droplets, the fluctuation range of the receding angle is considerably greater than that of the advancing angle, thereby rendering the receding angle as the primary determinant factor for droplet movement, and as the hydrophobicity of the surface improves, the fluctuation extent of the droplet’s receding angle experiences a significant diminution. Droplet motion on superhydrophobic surfaces comprises both slipping and rolling behaviors, the increased hydrophobicity of the surface and the larger tilt angle facilitate droplet movement in a slipping mode on the surface, within the experimental parameters, the proportion of rolling distance to slipping distance varies from 35 % to 15 %. This study has revealed innovative regulatory approaches for modulating the moving behavior of liquids on microstructured surfaces, potentially enabling the development of superior functional surfaces for fluid drag reduction or droplet manipulation in the future.