Smooth Metal Surfaces Research Articles

SURFACE QUALITY AND CORROSION RESISTANCE OF 316L STAINLESS STEEL ELECTROPOLISHED USING PHOSPHORIC – SULFURIC ACIDS

Electropolishing is an electrochemical surface finishing technique. It is commonly applied to equipment that requires a gleaming finish. This surface property is frequently required in 316L stainless steel (SS) medical implants. Electropolishing removes a thin layer from the metal's surface through electrochemical processes. This results in a very clean, smooth, and bright metal surface. The process parameters, such as electrolyte solution, electrical current, and electropolishing time, influence surface roughness and glossiness. The dissolution of metallic ions during the process may also affect the corrosion resistance of the treated material in addition to producing a shiny surface. This study investigated the surface glossiness, surface roughness, and corrosion of electropolished 316L SS. Electropolishing experiments on 316 SS were carried out using various H3PO4 (50%) and H2SO4 (32%) electrolyte solution compositions. The influences of electrolyte solution composition, electric current, and electropolishing time were studied. The results showed that increasing the H2SO4 content of the mixture and electropolishing the 316L SS for a longer period of time improved the surface roughness and glossiness. Under 10 Amp electric currents, the best surface glossiness was discovered. A corrosion test revealed that the electropolishing produced a Cr and Ni-rich layer that improved the corrosion resistance of the samples.

Bifunctional K3PW12O40/Graphene Oxide-Modified Separator for Inhibiting Polysulfide Diffusion and Stabilizing Lithium Anode.

Lithium-sulfur (Li-S) batteries are considered as promising candidates for next-generation batteries due to their high theoretical energy density. However, the practical application of Li-S batteries is still hindered by several challenges, such as the polysulfide shuttle and the growth of lithium dendrites. Herein, we introduce a bifunctional K3PW12O40/graphene oxide-modified polypropylene separator (KPW/GO/PP) as a highly effective solution for mitigating polysulfide diffusion and protecting the lithium anode in Li-S batteries. By incorporating KPW into a densely stacked nanostructured graphene oxide (GO) barrier membrane, we synergistically capture and rapidly convert lithium polysulfides (LiPSs) electrochemically, thus effectively suppressing the shuttling effect. Moreover, the KPW/GO/PP separator can stabilize the lithium metal anode during cycling, suppress dendrite formation, and ensure a smooth and dense lithium metal surface, owing to regulated Li+ flux and uniform Li nucleation. Consequently, the constructed KPW/GO/PP separator delivered a favorable initial specific capacity (1006 mAh g-1) and remarkable cycling performance at 1.0 C (626 mAh g-1 for up to 500 cycles with a decay rate of 0.075% per cycle).

Proliferating particle surface area via microbial decay has profound consequences for remineralisation rate: a new approach to modelling the degradation of sinking detritus in the ocean

Sinking detritus particles in the ocean help to regulate global climate by transporting organic carbon into deep waters where it is sequestered from the atmosphere. The rate at which bacteria remineralise detritus influences how deep particles sink and the length-scale of carbon sequestration. Conventional marine biogeochemical models typically represent particles as smooth spheres where remineralisation causes surface area (SA) to progressively shrink over time. In contrast, we propose that particle SA increases during degradation as microbial ectoenzymes cause a roughening of surfaces in a process similar to acid etching on previously smooth glass or metal surfaces. This concept is investigated using a novel model, SAMURAI (Surface Area Modelling Using Rubik As Inspiration), in which the biomass of individual particles is represented as a 3D matrix of cubical sub-units that degrades by progressive removal of sub-units that have faces in contact with the external environment. The model rapidly generates microscale rugosity (roughness) that profoundly increases total SA, giving rise to biomass-specific remineralisation rates that are approximately double those of conventional models. Faster remineralisation means less carbon penetrates the ocean’s interior, diminishing carbon sequestration in deep waters. Results indicate that both SA and microbial remineralisation are highly dynamic, as well as exhibiting large variability associated with particles of different porosities. Our work highlights the need for further studies, both observational and modelling, to investigate particle SA and related microbial dynamics in order to reliably represent the role of ocean biology in global biogeochemical models.

Bubble growth on a smooth metallic surface at atmospheric and sub-atmospheric pressure

Bubble growth rate is one of the most important parameters required for the development of accurate mechanistic nucleate boiling heat transfer models. It is also very important for understanding the hydrodynamic forces and the mechanism of bubble departure. This paper presents an experimental study on bubble growth measurements in saturated pool boiling of deionized water on a plain copper surface at atmospheric and sub-atmospheric pressure. The measurements were conducted using a high-speed, high-resolution camera with a microscopic lens. The mechanisms of bubble growth are discussed, while the microlayer evaporation mechanism has been evaluated and discussed using the measured bubble growth curve. The estimated contribution of microlayer evaporation to a single bubble growth is about 70 %, while the contribution of latent heat transfer (evaporation) to the total heat transfer rate from the surface is about 30 %. The remaining 70 % is due to other mechanisms, i.e. conduction and convection. These values were obtained based on the analysis of the bubble growth curve only and agreed with some researchers who conducted local heat transfer measurements using integrated sensors or infrared thermography. These detailed measurement techniques cannot be used with the thick copper block tested in the current study, which was also tested by many researchers in literature and is representative of industrially used surfaces. It was also found that the bubble departure mechanism at atmospheric pressure is due to a static balance between surface tension and buoyancy forces while at sub-atmospheric pressure, it was between buoyancy and liquid inertia forces. The pressure did not have a significant effect on the characteristics of the dynamic contact angle, which was also measured from the instantaneous images of the bubble. It was concluded also that the force balance required for the accurate prediction of departure diameter should be conducted when the two forces are equal, which occurred at time less than the departure time and dynamic contact angle of about 45. In most bubble departure models, researchers recommended the balance to be conducted at the moment of departure when the bubble forms a neck with contact angle of 900 (underestimation to the surface tension force). The analysis of one of the commonly used homogeneous growth models indicated that for homogeneous bubble growth models to be applicable in nucleate boiling, an allowance must be made for the fact that the degree of superheat varies with time during a bubble growth period.

A point cloud preprocessing method for complicated thin-walled ring parts with irregular section

Metallic W-ring is a typically complicated thin-walled ring part with irregular section (CTWRPIC). However, there is a lack of effective measurement methods to inspect its geometric quality in the forming process, which leads to the failure of finding the forming defects in time. Due to the smooth metal surface, complex section shape, small section size and annular closed overall structure, point cloud of the section profile obtained by the line laser scanners has serious noise, outliers and missing. To this problem, this article proposes a point cloud preprocessing method for CTWRPIC. In this method, historical measurement data based outliers statistics, initial-fine rigid registration and non-rigid registration of CAD model are introduced. Firstly, the optimal alignment of point cloud from the CAD model and measurement point cloud is realized by initial-fine rigid registration. Secondly, the point cloud of CAD model is transformed by non-rigid registration to approximate the measurement profile points, the transformed point cloud of CAD model is considered as the real profile. Thirdly, based on the transformed point cloud of CAD model and distance threshold, the adaptive removal of outliers and repair of missing are realized. Finally, the correction of profile point cloud noise is completed by combining the Alpha Shapes algorithm and the proposed repair method. Based on the proposed preprocessing method and a measurement platform equipped with line laser scanners, an on-machine measurement method for metallic W-ring is proposed, and experimental results demonstrate the advantage of the proposed method. Compared with the destructive inspection method, the mean value, standard deviation and root mean square of the distance deviation of the preprocessed point cloud are all within 11 μm.

Bubble growth models in saturated pool boiling of water on a smooth metallic surface: Assessment and a new recommendation

Prediction of bubble growth rate is very important for the development of accurate models for bubble departure diameter and thus the heat transfer rates in nucleate boiling. This paper presents an evaluation study to the existing homogeneous and heterogeneous bubble growth models using our experimental data for bubble growth in saturated pool boiling of deionized water on a plain copper surface. The experiments were conducted at pressures 1, 0.5 and 0.15 bar and superheat in the range 5.1 – 19.5 K. To start with, the paper presents a critical review on bubble growth models in homogeneous and heterogeneous boiling. It was found that homogeneous growth models achieved some partial agreement with the experimental data at some conditions and thus they should be used carefully in heterogeneous boiling. There was a good agreement between some of the models that were suggested based on the assumption that bubble growth occurs due to evaporation from the superheated boundary layer around the bubble. The models based on microlayer evaporation only could not explain the experimental data, i.e. partial agreement at some conditions. The model that predicted the data very well at all conditions was the “relaxation boundary layer” model by Van Stralen [25]. This model was generalized in the current study by suggesting two new empirical models for the departure diameter and departure time.

An up-conversion Ba3In(PO4)3:Er3+/Yb3+ phosphor that enables multi-mode temperature measurements and wide-gamut 'temperature mapping'.

At present, most fluorescent materials that can be used for optical temperature measurement exhibit poor thermochromic performance, which limits their applications. In this study, the phosphor Ba3In(PO4)3:Er/Yb was synthesized with a high doping concentration of Yb3+, and it emitted composition- and temperature-induced wide color gamut up-conversion luminescence from red to green. Four modes of fluorescence thermometry can be realized in the temperature range of 303-603 K, which is based on the ratio of fluorescence intensity between thermally coupled energy levels and non-thermally coupled energy levels, color coordinate shift, and fluorescence decay lifetime, respectively. The highest Sr value obtained was 0.977% K-1. Taking advantage of the fact that temperature can significantly change the luminous color of the phosphor Ba3In(PO4)3:0.02Er3+/0.05Yb3+, we demonstrated 'temperature mapping' on a smooth metal surface with multiple optical encryptions. These results indicate that the Ba3In(PO4)3:Er/Yb phosphor is an excellent fluorescent material for thermal imaging and has great application potential in temperature visualization measurement and optical encryption.

A New Configuration Method for Glass Substrate Transfer Robot Modules Based on Kansei Engineering

How to effectively match the relationship between users’ perceptual demands and the characteristics of industrial robot modules becomes a pressing issue when perceptual demands become a significant determinant of whether users purchase and employ industrial robots. In this regard, we propose a Kansei Engineering-based method for industrial robot module configuration, using the module design of a glass substrate transfer robot as an example. First, the method analyzes the perceptual demand characteristics of the target user, utilizing the semantic difference method, and then establishes a mapping relationship between the user’s perceptual demand and the robot design elements, utilizing the hierarchical inference method. On the basis of this mapping relationship, the robot module for transfer glass substrates is then designed. Finally, orthogonal design and conjoint analysis were used to effectively and objectively analyze user preferences for various module configuration alternatives. The results indicate that the industrial robot’s shape, color, and material are the three appearance characteristics that influence the user’s perceptual demands. The slender, rigid design features of the industrial robot, such as the streamlined drive shaft, lengthwise expanded body structure, integrated body structure, and hidden plugs, as well as the simple color scheme and smooth metal surface, are key elements in the industrial robot’s perceptual design. The turn shaft module and lift shaft module have respective weights of 35.040% and 31.120%, determining whether the glass substrate transfer robot can create a simple style. In the context of the widespread use of industrial robot modules, the methods and findings of this study offer new ideas for the design of industrial robot modules and broaden the research and applications of Kansei Engineering in module design.

Macrophages and vimentin in tissues adjacent to megaprostheses and mesh in reconstructive surgeries

ABSTRACT In reconstructive surgery using artificial materials after wide resection, soft tissues are usually adjacent to metal surfaces or mesh. The purpose of this study was to provide histological evaluation of the soft tissues adjacent to the metal surfaces of megaprostheses and mesh. Tissues from revision surgery of megaprosthesis and from wide resection after recurrent thoracic wall sarcoma were used. Histological analysis was evaluated by hematoxylin/eosin (HE) and Masson’s trichrome staining, and by immunohistochemical staining for markers including cluster of differentiation 68 (CD68), vimentin, collagen type and S100A4. Soft tissue adherence to the smooth metal surface of Ti alloy was not observed. On the surface of capsule, CD68- and vimentin-positive cells formed a thin layer. In contrast, soft tissue adherence to a rough-surface cobalt chrome alloy was observed. Capsule was not apparent for this tissue, in which CD68- and vimentin-positive cells were aggregated randomly. In the resected tissues of recurrent chest wall sarcoma, muscles showed connections to connective soft tissues but did not invade to the inside of the mesh. Around the polypropylene mesh, large numbers of CD68- and vimentin-positive cells were seen. On the ePTFE, small numbers of CD68-positive cells were observed, while a larger number of the cells were vimentin positive. High accumulation of S100A4-positive cells was observed at the metal surface and polypropylene surface. Cells were strongly positive for CD68 and vimentin in tissues adjacent to metal and mesh surfaces. Macrophages and vimentin may play important roles in the foreign body reaction to metal and mesh, and so may contribute to encapsulation and fibrosis.

Spray Coated Cellulose Nanofiber (CNF) Film as an Eco-Friendly Substrate for Flexible and Printed Electronics

Cellulose nanofiber is an eco-friendly nanomaterial used for fabricating various functional materials. It is an alternative for synthetic plastic and other petroleum derived materials. Due to demand of CNF film, fast and rapid method for fabrication of CNF film is required. A new method on spray coating to prepare smooth cellulose nanofiber (CNF) films was developed. In this method, spraying CNF suspension onto a smooth and polished metal surface was carried out and then allowed the spray coated wet film to dry in air under standard laboratory conditions. Spraying has notable advantages such as contour coating and contactless coating with the base substrate. The basis weight and thickness of the CNF film is tailorable by adjusting CNF suspension in spraying process. CNF film prepared via spray coating has unique two-sided surface roughness with the surface in contact with the base substrate or metal side much smoother than the air-contact side. The surface roughness is one of the controlling parameter in the application of the CNF film as a substrate for flexible and printed electronics. The RMS roughness of the two surfaces investigated by Optical Profilometry [OP] was found to be 2087 nm on the rough side and 389 nm on the spray coated side, respectively. The spray coated CNF film has ultra-high smoothness on the side exposed to the polished stainless steel surface. The factors including the size of cellulose fibrils and surface smoothness of base surface that control the roughness of the film are currently being investigated and will be discussed in this chapter. The surface smoothness requirements for substrate applications in flexible and printed electronics will be discussed.

Bubble Growth on a Smooth Metallic Surface at Atmospheric and Sub-Atmospheric Pressure

Bubble Growth on a Smooth Metallic Surface at Atmospheric and Sub-Atmospheric Pressure

Wear properties of textured lubricant films filled with graphite and polytetrafluoroethylene (PTFE) via laser surface texturing (LST)

One of major issues to laser processing lies in unavoidably existing high points at the edge of affected zones. However, these high points can act as anchorage points to tackle the problem that some functional materials are difficult to manufacture completely lubrication films on smooth metal surfaces. In this study, two kinds of textured lubricant films, namely graphite filled textured lubricant film and polytetrafluoroethylene (PTFE) filled textured lubricant film, were investigated by means of laser surface texturing. Such PTFE/graphite lubrication films and reverse use of the capture function of surface texture microconcaves were employed to enhance the tribology properties. The friction coefficient of these two films sliding against PTFE/Kevlar fabric composites was decreased by 10–45%, and the time to reach a stable state was shortened 100 times. The wear mechanism of these films is adhesive and fatigue wear and the transfer films are complete and continuous.

DEVELOPMENT AND ANALYSIS OF THE ACCURACY OF ENGINEERING METHODS FOR DETERMINATION OF INTERACTION VOLUME FOR CALCULATION OF THE TIGHTNESS OF NON-LUBRICATING CYLINDER-PISTON SEALS

Based on the theory of stochastic processes, methods of engineering calculation of the contact volume for the calculation of the tightness of non-lubricating cylinder-piston seals of compressors have been developed. The result is the creation of methods for calculating the tightness (duration of gas flow) in non-lubricating cylinder-piston metal-polymer seals, as well as assessing the accuracy of the created methods for piston seals. The article considers the elastic contact of a strongly anisotropic rough surface (polymer surface) with a smooth (metal) surface. The dependence of the intercontact gas volume on the complex of contact conditions based on the theory of stochastic fields is investigated. An estimate of the error that occurs when replacing the exact formula for calculating the contact volume with an approximate formula is performed. The values ​​calculated according to the exact and calculated formula of the consolidated inflow differ by no more than 0.17 percent. Accurate methods for calculating the tightness of non-lubricating cylinder-piston seals for molecular and viscous modes of gas flow, which is the basis for practical calculations of the tightness of the seals of non-lubricating pneumatic compressors, are theoretically substantiated and developed. The dependence of the contact volume, the effective level of deformation and the average height of the gap on the set of contact conditions has been studied. It is established that at low loads the deformation level, the effective deformation level, the reduced contact volume and the reduced average gap height are numerically equal. The values ​​calculated by the exact and calculated formula of the contact volume differ by no more than 0.17 percent at K 1 and no more than 0.00029 percent at K> 1.

Synergistic Effect of Iodide Ion and N‐methyl‐N,N,N‐trioctylammonium Chloride on Corrosion Inhibition of Carbon Steel in 0.5 M H2SO4: Experimental and Computational Approach

AbstractAn ionic liquid Aliquat 336 was for the first time analyzed for its adsorption and corrosion inhibition behavior for carbon steel surface in 0.5 M H2SO4. The inhibition performance was studied using gravimetric and electrochemical techniques supported by surface analytical measurements. The inhibitor exerted an efficiency of 96.53 % at 12×10−6 M. Significant improvement was achieved with iodide ions, which at 3.01×10−4 M, produced a remarkable rise in the efficiency to 99.03 %. The adsorption of the inhibitor on the metallic surface followed the Langmuir isotherm at 298 K in the concentration range of 2.47 to 12.37×10−6 M. Polarization studies indicated a mixed‐mode of inhibitor action with the cathodic predominance. The SEM studies showed a smooth metal surface in contact with the inhibitor, and a representative decrease in surface roughness was observed by AFM studies. Monte Carlo simulations showed inhibitor adsorption in a flat orientation on the metal surface with high adsorption energy.

Reflection interference removal for infrared thermography images based on GAN

Reflection in images is common and the removal of complex noise such as image reflection is still being explored. The problem is difficult and ill-posed, not only because there is no mixing function but also because there are no constraints in the output space (the processed image). When it comes to detecting defects on metal surfaces using infrared thermography, reflection from smooth metal surfaces can easily affect the final detection results. Therefore, it is essential to remove the reflection interference in infrared images. With the continuous application and expansion of neural networks in the field of image processing, researchers have tried to apply neural networks to remove image reflection. However, they have mainly focused on reflection interference removal in visible images and it is believed that no researchers have applied neural networks to remove reflection interference in infrared images. In this paper, the authors introduce the concept of a conditional generative adversarial network (cGAN) and propose an end-to-end trained network based on this with two types of loss: perceptual loss and adversarial loss. A self-built infrared reflection image dataset from an infrared camera is used. The experimental results demonstrate the effectiveness of this GAN for removing infrared image reflection.

EXPERIMENTAL SETTING FOR TESTING THE BOND STRENGTH BETWEEN METAL ALLOY AND PEEK

Purpose: The aim of the article is to present an experimental setting for bending strength testing of metal specimens covered with PEEK. Materials and methods: Three groups of metal specimens made of cobalt chromium alloy are produced using the lost wax technique: group 1 – specimens with a smooth metal surface; group 2 – sand blasted metal surface; group 3 - sand blasted metal surface with retention crystals. The shape and size of the specimens are designed to correspond to the retentive elements of the apparatus for micro tension and micro pressure LMT 100. PEEK is pressed over the specimens, and after thermal cycling, the bond between metal alloy and PEEK is studied using bending strength three-point micro testing. Results and discussion: The experimental setting is focused on the type of specific contact surface between the two materials. The design corresponds to the requirements of apparatus LMT 100 and allows the production of a big number of specimens. Because of the thermal regime of BioHPP pressing, it is impossible to add groups of specimens using contemporary adhesives on the metal surface. Conclusion: Created specimens allow strength investigation by three-point bending micro testing. The experimental setting provides the production of a big number of specimens with the same shape and size.

Unraveling the synergistic effects of solid surface material and temperature on the contact angle of water under an elevated pressure: An experimental study

HypothesisIn terms of the Young’s equation, the temperature dependence of liquid-solid contact angle is affected by the surface material, so the wetting behavior could be tuned by both changing the temperature and surface material. However, the synergistic effects of surface material and temperature on the water contact angle remain unclear, especially at elevated temperatures. ExperimentsIn this study, a systematic characterization of water contact angle against various smooth metallic and nonmetallic surfaces was conducted for temperatures up to 300 ℃ in a high-pressure chamber at 15 MPa. The measured results were finally compared with the predictions made by the sharp-kink approximation model. FindingsNot surprisingly, it was observed the temperature-dependent water contact angle is sensitive to the type of solid surface. The temperature coefficients and critical temperature points on the contact-angle-temperature curves can be manipulated by altering the surface material. However, the influence of surface material is weakened by raising temperature, thus leading to the nearly consistent temperature-dependent water contact angle over 120℃. Additionally, the necessity of investigating the internal flows within the water drops was highlighted to unravel the positive temperature correlation of the water contact angle at high temperatures, in view of the presence of non-spherical-cap-shaped drops.

Directional Raman scattering spectra of metal–sulfur bonds at smooth gold and silver substrates

AbstractThe gold–sulfur (Au–S) and silver–sulfur (Ag–S) bonds are integral to the surface modification of metal films with alkanethiol monolayers. Although the metal–sulfur bond can be characterized with surface‐enhanced Raman spectroscopy (SERS) at roughened metal films, some applications require or perform better when using a smooth metal surface, which is not suitable for SERS signal enhancement. Directional‐surface‐plasmon‐coupled Raman scattering (directional Raman scattering) is an approach to measure metal–sulfur bonds on smooth metal films with sub‐monolayer sensitivity. The metal–sulfur bonds formed from a benzenethiol monolayer on smooth planar gold or silver films are observed in the directional Raman scattering spectra between 240 and 270 cm−1; the signal‐to‐noise ratio of the Au–S Raman peak is 60. Importantly, the directional Raman scattering signal measured with smooth metal surfaces can be simply modeled and easily compared across many samples. Directional Raman scattering can also be measured at roughened metal films, which makes it applicable for many analyses.

Enhancing the performance of light field camera by pattern projection

For industrial three-dimensional (3D)-measuring applications as well as for other applications such as driver assistance systems in vehicles, a high-quality reproduction in a depth map calculation is of paramount importance. Yet to date, light field cameras still exhibit severe problems in imaging homogeneous surfaces such as smooth metallic surfaces, plastics, or semiconductor materials. On those, the necessary contrast for determining the topography is not present or too weak. Here, we present an innovative approach to improve the performance of light field cameras (also called plenoptic cameras) for various applications in 3D measurement technology. More specifically, we show that this disadvantage can be avoided using structured lighting pattern and analyze various lighting patterns (with respect to geometry, size, regularity, etc.) used to improve the performance of the algorithm in greater detail. In addition, different ways of projecting the pattern have been examined with regard to their advantages and disadvantages. We perform a systematic investigation of the impact of structured light illumination with regard to different object materials, object geometries, and illumination patterns as well as illumination sources. These examinations further comprise the analysis of environmental influences and magnitude of measurement deviations in a light field camera measuring set-up. Summing up, we investigated experimentally the influence of structured illumination on the performance of 3D depth information without the need of additional phase information.

Gravimetrical, theoretical, and surface morphological investigations of corrosion inhibition effect of 4-(benzoimidazole-2-yl) pyridine on mild steel in hydrochloric acid

Abstract The corrosion inhibition efficiency of the novel pyridine namely, 4-(Benzoimidazole-2-yl)pyridine has been studied for mild steel in a 1 M hydrochloric acid environment by utilizing gravimetrical techniques. The synthesized inhibitor exhibits a significant inhibitive efficiency of 93.8% at 0.005 M. The adsorption isotherm of the investigated inhibitor on mild steel surface obeys the Langmuir isotherm. Surface morphology investigated by utilizing scanning electron microscopy (SEM) demonstrates a smooth metal surface with the addition of 4-(Benzoimidazole-2-yl)pyridine in a hydrochloric acid environment. Quantum chemical calculations using density functional theory (DFT) have been used to investigate the molecular structure and behavior of 4-(Benzoimidazole-2-yl) pyridine as a corrosion inhibitor. Different parameters have been calculated using DFT, such as energies of highest occupied molecular orbital and lowest occupied molecular orbital (EHOMO and ELUMO), energy gap (∆E), and dipole moment (μ). These parameters were important to elucidate the behavior of the investigated molecule as a corrosion inhibitor in acidic solution and also suggest the mechanism of inhibition.