Surface Processing Method Research Articles

Extraction of isotropic and anisotropic components for optical surface micro-metrology based on the two-dimensional power spectral density analysis

Extraction of surface characteristics is essential during surface processing and optical inspections. In this work, we propose a new extraction method by dividing the global feature within multiple directions into isotropic and anisotropic components and combining noise filtration, two-dimensional component extraction, and fast reconstruction. The mathematical descriptions of global and local features were derived. The noise by holes, scratches, and finite sampling points was restrained by Bearing Ratio analysis, Hough transform, and Welch window operation. The isotropic and anisotropic surface components were extracted in the two-dimensional power spectral density domain, reconstructed in the two-dimensional Fourier domain, and inversed in Cartesian coordinates. Five surfaces with anisotropic structural characteristics ranging from zero to two dimensions were analyzed. The general applicability was proved according to the consistency between surface processing methods and extracted results. A chemical mechanical polishing experiment was designed and accomplished to verify the sensitivity of the extraction method. The subtle variation in surface morphology was captured on the reconstructed surfaces near the polishing end-point, confirming its detectability on weak anisotropic components. This process-oriented surface extraction method can achieve qualified results without transcendental knowledge of surface conditions and offers openness to various surface evaluation criteria by statistical roughness indicators, which supports surface inspection for multiple surface processing techniques.

Research on Surface Processing Method of Pulse Transmission Signal of Amplitude-Modulated Drilling Fluid in 10,000-m Deep Wells

Conventional Measurement-While-Drilling (MWD) technology is unable to function statically at the predicted temperatures of deep formations exceeding 200 °C in wells reaching depths of 10,000 m. It is limited to measuring downhole engineering parameters through purely mechanical means, such as inclination. However, the accurate long-distance transmission of drilling fluid pulse signals poses a significant bottleneck, restricting the application of these mechanical measurement methods. To address these issues, this paper develops and designs an algorithm to identify and analyze the amplitude characteristics of deep well mud signals. By employing a signal coding algorithm, a signal processing analysis method, and a signal feature recognition algorithm based on grey correlation degree, we construct a signal recognition method capable of decoding mud amplitude encoded signals. Key techniques such as filtering, smoothing, and feature extraction are utilized in the signal processing, and the proposed method’s effectiveness is verified through the analysis of collected signals. Furthermore, long-distance simulation analysis software is developed to evaluate waveform distortion during extended transmission, confirming the feasibility of the recognition algorithm. Laboratory experiments demonstrate that this algorithm can accurately recognize and demodulate signals generated by mechanical inclinometer structures, providing a novel decoding method for signal transmission in deep and ultra-deep wells.

Influence of different processing techniques for prosthetic acrylic resins in the surface roughness parameters: a research article

BackgroundDifferent processing techniques are employed to obtain poly (methyl methacrylate) (PMMA) with consistent surface quality in terms of topography and tribological function. The purpose of this research is to evaluate its influence on the surface height distribution.MethodsIn this research, samples of conventional and CAD/CAM acrylic resins were prepared. The following surface roughness parameters were extracted from the profilometric readings: arithmetic mean roughness (Pa), skewness (Psk) and kurtosis (Pku). Profilometric profiles were additionally obtained.ResultsThe average roughness (Pa) with the conventional technique was significantly higher compared to CAD/CAM (t = 4.595; P < 0.001). Heat-cured resins presented the highest mean Pa (F = 6.975; P = 0.06). Heat-cured and milled resins show lower coefficient variation (CV) values, indicating more consistent surface finishing. The surface profiles revealed distinct characteristics in terms of skewness and kurtosis.ConclusionsThe surface processing method, chemical composition and resin type significantly influence the surface finishing of the resin. The CAD/CAM resins exhibited superior results in terms of surface arithmetic mean roughness (Pa). However, heat-cured resin revealed to present the better surface consistency.

Development of an artificial neural network based-prediction model for bond strength of FRP bars in concrete

Fiber-reinforced polymer (FRP) bars have garnered increasing attention in recent years due to their superior corrosion resistance, offering a potential solution to the significant drawback of steel corrosion in concrete. For the widespread utilization of FRP bars in concrete structures, determining the bond strength between FRP bars and concrete is a crucial topic. This study seeks to develop a prediction model to estimate the bond strength of FRP bars in concrete, utilizing an extended dataset from 1010 pull-out tests. Initially, the study evaluates the applicability of several bond strength formulas from existing codes. Subsequently, two prediction models, namely a multivariate linear regression model and an artificial neural network (ANN) model, are introduced for estimating the bond strength of FRP bars in concrete. The results indicate that the correlation between the evaluation values of existing formulas and the experimental value is very low. This is because these formulas have not yet been updated to encompass the expanded usage scopes of FRP bars with various surface processing methods and types of concrete. While the multivariate linear regression model outperforms these formulas, its accuracy is still relatively low; in contrast, the ANN demonstrates superior performance, achieving an R^2 value for both the validation and test set of more than 0.92. The findings highlight that, when considering a broader range of applications, the ANN serves as a robust tool for accurately predicting the bond strength of FRP bars in concrete, in comparison to traditional formulas and linear regression models. This assessment approach provides engineers with a convenient, high-precision tool for designs utilizing various forms of FRP bars and diverse types of concrete in practical design scenarios

Characterization and ion-irradiation studies of typical microstructures in nuclear graphite

Nuclear graphite is an important structural material for advanced gas cooled reactors and molten salt reactors. Graphite microstructures are always accompanied with typical pores or cracks which plays an important role in nuclear graphite behaviors. A new surface processing method involving ion milling and fast oxidation is used here to characterize typical microstructures from the large-size calcination cracks in fillers to very small quinoline insoluble particles in NBG-17 and NBG-18 graphites. By using this surface processing method and ion irradiation technique, an attempt is made to explore the microstructural basis of graphite irradiation behaviors. Heating-induced relaxation of graphite microstructures is observed, indicating the presence of residual stresses in nuclear graphite. Creased graphite sheets are identified on ion-milled surface and are believed to accommodate a-axis shrinkage of graphite crystallites at the beginning of irradiation, which is consistent with the initial plateau of slow dimensional shrinking. Compared to NBG-17 graphite, NBG-18 is found to have much more calcination cracks which contract during irradiation, resulting in a deeper volume shrinkage of NBG-18. The quinoline insoluble particles containing chaotic structures are shown to severely contract and separate from surrounding structures, leading to voids in between. Both NBG-18 and NBG-17 have abundant quinoline insoluble particles, which might make a contribution to their smaller volume shrinkage than other medium-grain graphite.

Femtosecond laser surface processing combined with thermal oxidation for enhancing corrosion resistance of AZ31B magnesium alloy in chloride solutions

A novel method of ultrafast femtosecond laser surface processing (FLSP) combined with the post thermal oxidation (TO) treatment was employed to improve the corrosion resistance of AZ31B magnesium (Mg) alloys. FLSP with laser powers (< 100 mW) mainly creates the nanostructures on AZ31B alloy surfaces, while the higher laser powers (> 200 mW) induce the hierarchical micro/nanostructures. According to the electrochemical results, the corrosion resistance of AZ31B alloys in Cl− solutions is weakened after the FLSP. However, an obvious enhancement in corrosion resistance is found when the femtosecond (fs) laser-processed samples subjected to the TO treatment in the temperature range from 100 °C to 280 °C. TO treatment actually supports the oxidation and growth of the nanostructure to form a dense film, considerably improving its protective ability and enhancing the corrosion resistance of Mg alloys in Cl− solutions. The uniform corrosion is evidently inhibited and localized corrosion emerges on laser-processed samples after the TO treatment.

From Waste to Strength: Unveiling the Mechanical Properties of Peanut-Shell-Based Polymer Composites

Peanut-shell-based polymer composites have gained significant attention as sustainable and cost-effective materials with potential applications as food packaging films, ceiling tiles, insulation panels, supercapacitors, and electrodes in various industries like the packaging industry, construction, furniture, and electronics. This review article presents a systematic roadmap of the mechanical properties of peanut-shell-based polymer composites, analyzing the influence of factors such as filler content, surface modification techniques, interfacial adhesion, and processing methods. Through an extensive literature review, we highlight the mechanical properties of peanut-shell-based polymer composites. Furthermore, challenges and ongoing research efforts in this field are discussed. This comprehensive review provides valuable insights for researchers, industry professionals, and policymakers, promoting the development and utilization of peanut-shell-based polymer composites for various applications.

Efficiency of photoactivated implant surface processing method for increasing stability of dental implant

Stability of the implants is based on its endurance, which is very important for further decision and prognosis. For creation of hydrophilic surface were instilled the different methods of treatment. At the same time, the efficiency of photoactivation method and its perspectives for the increasing of the implant stability is not yet enough researched and needs the special attention. The aim of the study is to assess the stability of two groups of implants, evaluated either by the grit blasting processing and acid etching alone, or with additional photoactivation, using resonance frequency analysis (RFA). 101 implants of 56 patients (20 men and 36 women) were studied, 53 of them were treated with grit blasting processing and acid etching, and 48 with photo activation. The Implant stability quality (ISQ) was measured using the RFA method on the day of the implant set, and after 2, 8 and 16 weeks for each implant. For statistical analysis was used software package Statistica 10.0 for Windows, with following calculating M (arithmetic mean) and m (error of the arithmetic mean). Differences at p&lt;0.05 were signed considered probable. After 8 weeks, higher indices of the stability of the implant were established in the group where photoactivation was applied (for 4,1 points ISQ, p&lt;0,05). After 16 weeks, the implant stability quality factor was likely to be higher after the photoactivated surface of the implant (3,9 points ISQ, p&lt;0,05). When comparing the stability ratio of the upper-jaw and lower-jaw implants in each group, both groups showed a higher coefficient of stability of the implant for the lower jaw than for the upper-jaw implants at each stage of observation (p&lt;0,05). The average ISQ value was higher in implants with super hydrophilic surface, treated with a photocatalytic effect than in those, who did not receive such treatment, i.e. photoactivation of the surface of the implant promotes osteointegration by increasing the hydrophilic surface. Keywords: implant's stability, implant stability quality, photoactivation, resonance-frequency analysis.

Shear Bond Strength of Two Self-Etching Adhesives to Air-Abraded Dentin: An in Vitro Study

Background: The aim of this research was to study the effect of air-abrasive treatment of dentin on the chemical composition of its surface and the adhesion strength of 2 self-etching adhesive systems (AS). Methods and Results: Powders based on aluminum oxide (Al2O3) (27µm) (KaVo, Biberach, Germany), sodium bicarbonate (NaHCO3) (40µm) (AIR-FlOW Classic Comfort, EMS, Nyon, Switzerland), and erythritol (14µm) (AIR-FLOW Plus, EMS, Nyon, Switzerland) were used for the air-abrasive treatment of adhesive surfaces. Bonding steps were carried out with Single Bond Universal (SBU) (3M ESPE, USA) and Bond Force 2 (BF2) (Toquyama, Japan). The adhesion strength of composite to dentin was evaluated on 80 samples prepared in accordance with the Ultradent Shear Bond Strength test. All samples were divided into 4 groups depending on the method of dentin surface processing. In the samples of Group 1 (n=20), aluminum oxide was used for the air-abrasive treatment of dentin. In Group 2 (n=20) and Group 3 (n=20), samples were treated using powders based on sodium bicarbonate and erythritol, respectively. Group 4 (control, n=20) included tooth samples in which the dentin surface was not air-abraded after preparation with carbide burs. Then, each group was divided into 2 subgroups (Sub-A and Sub-B) depending on the type of adhesive system used. Adhesive resin was applied and polymerized in accordance with the manufacturer’s instructions. Single Bond Universal (SBU) was used for the samples of Sub-A, and Bond Force 2 (BF2) (Toquyama, Japan) was used for the samples of Sub-B. Scanning electron microscopy and determining the surface elemental composition of samples were carried out on an SEM-EVO MA 10 (Carl Zeiss) and energy dispersive X-ray spectrometer with EDS Aztec Energy Advanced X-Act (Oxford Instruments). It was concluded that air-abrasive treatment of the dentin surface does not enhance the adhesion strength of composite material when using self-etch AS. Also, it was noted that the pH level of self-etch AS is not a crucial feature in determining the strength of the filling-tooth interface. The resulting variations in the elemental composition of dentin surface after air-abrasion with various mixtures and their effect on the efficacy of the different AS require further in vitro studies.

Reflection Coefficient Estimation of Femtosecond Laser Surface Processing Using Support Vector Regression

An image analysis-based Reflection Coefficient (RC) estimation method of femtosecond laser surface processing for the blackening of X-ray imaging sensor shell is proposed. The Support Vector Regression (SVR) is used for RC computation and both an offline and an online steps are considered in this method. Regarding offline step, the typical laser process parameters are set to perform surface processing and Scanning Electron Microscope (SEM) images are recorded. Then a series of image features are computed and both the computed image features and typical laser parameters are used to train SVR: the training dataset includes the laser line space, laser beam diameter, natural logarithm of laser power divided by laser frequency, and image features of Gray-Level Co-occurrence Matrix (GLCM); the supervising data are laser ablation diameters. As for online step, when SEM image data are recorded after laser processing, the trained SVR is used to predict laser ablation diameter and then the RC can be computed by laser ablation model. Many experiment results have verified the effectiveness of our proposed method, and the RC estimation accuracy can be better than 90.0%.

Additive manufacturing 3D customizable low-cost superwetting polyacrylate-based hierarchically micro-nanoporous lattice anode for energy-saving large-current-density water splitting application

In this paper, varieties of 3D polyacrylate (PA)-based electrodes were precisely built by digital light processing (DLP) 3D printing technology combining special induced chemical co-deposition surface processing method. This novel electrode fabrication technology exhibits the features of low-cost, no template requirement, customizable freedom design and controllable hierarchically micro-nanoporous architecture characteristics. The studies show that unique 3D geometry structure design will facilitate the enhancement of the electrochemical active surface area, wetting properties and oxygen evolution reaction (OER) catalysis performance for PA-based lattice electrodes. The as-prepared superwetting thiourea dioxide (TDO) type PA-based body-centred cubic with circular struts (BCCCS) lattice (1.0 mm) electrode as water splitting anode drives 1000 mA/cm2 large-current-density at 1.55V (vs Reversible Hydrogen Electrode (RHE)) potential, which is 280 mV lower than the potential of the commercial Ni foam-based anode. This result shows obvious energy-saving advantage in industrial water splitting application area. Notably, the PA-based BCCCS lattice (1.0 mm) anode can stably drive 1000 mA/cm2 current density for at least 10 h in alkali electrolyte and obtains up to 100% anode faraday efficiency. This work provides new idea for high performance energy-saving electrodes and expands the application scope of additive manufacturing technology.

Enhancement of flow boiling heat transfer by laser-induced periodic surface structures using femtosecond laser

This study proposes a new surface processing method using a femtosecond laser to enhance the flow boiling heat transfer in a single mini/micro-channel duct. The suggested method is suitable for mini/micro-channel surface processing because the femtosecond laser with a short pulse duration (∼220 femtoseconds) simplifies the fabrication procedure and minimizes the thermal damage of surfaces during laser processing. Three types of laser-induced surfaces different in the nano-surface structure were fabricated. Three surfaces include laser-induced periodic surface structure (LIPSS), micro-groove covered clustered cavity by low fluence (MGCC-LF), and micro-groove covered clustered cavity by high fluence (MGCC-HF). Flow boiling heat transfer of each surface was experimentally investigated through a comparison with that of the plain copper surface in single-channel experiments. Experimental results demonstrated that LIPSS enhanced the boiling heat transfer by increasing the bubble nucleation sites with a self-organized nanosized ripple structure. Consequently, the MGCC-HF surface with nanosized clustered cavities and hydrophilic characteristics has the most prominent flow boiling heat transfer and critical heat flux enhancement. This enhancement is due to a synergy between increased nucleation sites and the wicking effects, promoting liquid rewetting and hindering local dry out. The present study confirmed that the flow boiling performance of the metal surface could be significantly improved through a relatively easy and fast process using a femtosecond laser.

Surface wettability control on zircaloy-4 by nanosecond Nd:YAG laser with beam homogenizer

We introduce the laser-induced surface processing (LISP) method that imparts hydrophilicity and hydrophobicity using a Nd:YAG nanosecond laser, especially the high-fluence (HF) condition for fast processing and the low-fluence (LF) condition to control the surface wettability. A prime example of HF processing is laser shock peening, where we show the potential to achieve both strength enhancement and wettability in materials. This could be a new advantageous feature in areas such as reactor maintenance. We combined a beam homogenizer with LISP to increase processing efficiency. The beam homogenizer realizes a uniform fluorescence distribution in the beam area and, at the same time, makes the beam rectangular to increase work efficiency. The maximum contact angle was 123.8° for the zircaloy-4 specimen through HF processing with the beam homogenizer. We also showed that nanosecond laser-induced periodic surface structures could be generated by combining LF processing with specific conditions of a beam homogenizer. This could produce a superhydrophobic surface with contact angles up to 166° on zircaloy-4 or achieve a near superhydrophilic surface with a contact angle of 17.9° depending on the processing conditions.

Formation of coatings with technologies using concentrated energy stream

Abstract A number of modern surface processing methods use an energy flux. The examples include electro-spark deposition (ESD) and laser beam processing (LBP). The work concerns the study of Cu-Mo coatings deposited on C45 carbon steel, which were then eroded with a laser beam. The analysis included the analysis of the microstructure, measurements of macrogeometry and microhardness, corrosion resistance tests of selected areas after laser treatment. The coatings were applied with ELFA-541 and subjected to Nd:YAG laser treatment with variable laser parameters. The problem presented in the work can be used to extend the knowledge of the areas of application of ESD coatings, especially in sliding friction pairs.

A review on friction stir processing over other surface modification processing techniques of magnesium alloys

An enormous amount of research has been conducted on aluminium alloys in friction stir processing (FSP), despite magnesium alloys reporting severe weight reduction when compared to aluminium alloys; a very slight amount of research has testified for FSP of magnesium alloys. Magnesium is highly reactive and susceptible to corrosion in the presence of an aggressive environment. This highly corrosive nature of magnesium limits its applications. Surface properties like crystal structure, composition, and microstructure influence the corrosion and wear properties of the material. Coating techniques and alloying techniques like laser surface modifications are performed to passivate the magnesium surface from corrosion. Coating techniques, however, have been found to be insufficient in corrosion protection due to coating defects like pores, cracks, etc, adhesion problems due to poor surface preparation of the substrate, and impurities present in the coating which provide microgalvanic cells for corrosion. The current study gives a detailed overview of different types of surface modification methods, such as physical vapour deposition, chemical vapour deposition, chemical conversion coating, and ion implantation coating techniques, and also focuses on a few alloying or surface processing methods, such as laser surface modification – namely laser surface melting, laser surface cladding, laser shot peening, laser surface alloying and FSP. FSP is a novel surface modification method derived from friction stir welding, which modifies the microstructure and composition of surface layer without changing the bulk properties to enhance corrosion resistance. FSP enhances and homogenizes the microstructure but also eliminates the breakup of the brittle-network phases and cast microstructure imperfections. Indeed, FSP can produce particle and fibre-reinforced magnesium-based surface composites. FSP empowers the manufacturing of magnesium by adding additives. The different methods of coating and surface modification are compared with FSP.

Novel dual-functional implants via oxygen non-thermal plasma and quaternary ammonium to promote osteogenesis and combat infections

ObjectiveImplant-related infections are a primary reason for implant failures that affect millions of patients. It is of paramount importance to develop novel implants that possess the dual functions of osteogenesis-promotion and antibacterial activity. The objectives of this study were to: (1) develop novel dual-functional titanium (Ti) implants by combining oxygen non-thermal plasma and covalent bonding of antibacterial organosilicon quaternary ammonium monomers; (2) investigate the physicochemical properties, bioactivity and antibacterial effects of the modified implants for the first time. MethodsSurface characteristics of the modified Ti surfaces were tested. Adherence and viability of rat bone marrow-derived stem cells (rBMSCs) on the surface were evaluated. Metabolic activity of biofilm on the surfaces were measured. The stability of the dual-function after 5000 thermal cycles was also evaluated. ResultsThe presence of chemical bonding between Ti and organosilicon monomers demonstrated covalent immobilization of the antibacterial agents. The water contact angle of the treated Ti surfaces decreased from 70.98 ± 3.68° to 59.86 ± 4.91°. The adhesion and proliferation of rBMSCs on the modified Ti were increased by 40%, compared to control group (P < 0.05). The metabolic level of biofilms on modified Ti were reduced by more than half, compared to control (P < 0.05). The modified Ti implants exhibited cell-promotion and antibacterial stability after thermal cycles. SignificanceThe new dual-functional Ti implant is promising to promote osteogenesis while simultaneously preventing infections. Furthermore, the novel surface modification and processing methods have applicability to enhancing a wide range of other implants to improve bioactivity and combat infections.

Rapid surface preparation for three-dimensional characterization of defect and microstructure of metal additive manufacturing using electrochemical jet

Process-induced volume defects and unsuitable microstructure have inhibited the effective quality assurance of parts manufactured by selective laser melting (SLM). Elucidating the complex interaction between the process, defect/microstructure, and performance is of critical importance. In this work, we have developed and demonstrated the capabilities of an electrochemical jet surface processing (EJSP) method to easily and effectively uncover defects and unveil the crystal microstructure and fusion mechanism in SLM parts of SUS316L and AlSi10Mg respectively. Experiments show that the EJSP method is highly effective in localized three-dimensional microstructural unveiling which eliminates the need for conventional sample preparation by polishing, and internal defects and retained fusion signatures at multiple layers are readily identified within seconds. Furthermore, EJSP unveils three-dimensional structural information at both micro- and nano-scale to facilitate crystallography and phase analysis. This unique approach has high potential to significantly improve qualification methods of SLM parts, which benefits in-depth research of microstructure characteristics and their formation mechanism in the SLM process with high efficiency and low cost.

Research on Surface Integrity Manufacturing of Bearing Ring Raceway Based on Plasma Polishing Principle

Plasma polishing technology is a new ultra smooth surface processing method with low cost, no pollution and no waste. It has been widely used in semiconductor industry and optical component manufacturing, but the research on the processing and manufacturing of key mechanical parts is still in the exploratory stage. In this paper, by using RC-ECMA150KVA plasma polishing equipment, plasma polishing technology is used to solve the surface integrity manufacturing problem of large-size rolling bearing ring raceway, which not only improves the processing quality of ring surface, but also realizes the function of surface corrosion and surface modification, and greatly improves the high service performance of rolling bearing.

Proliferation of mouse fibroblasts and osteoblastic cells on ZrO2-, SiO2-, and ZnO-deposited pure titanium discs using atomic layer deposition

Thin films of ZrO2 (ZR), SiO2 (SI), and ZnO (ZN) were deposited on pure titanium (Ti) discs using the atomic layer deposition (ALD) technique. The eluted amounts of Zr, Si, and Zn were measured using an inductively coupled plasma atomic emission spectrometer. The amounts of Zr and Si were below the detection level, while a small amount of Zn was detected in ZN. Cell proliferation in the samples was analyzed using the water-soluble tetrazolium salts (WST) assay. The number of L929 and MC3T3-E1 cells on ZR and SI increased over time. However, the number of both cells did not increase in ZN. This study highlights the possibility of depositing thin films on dental implants with complex shapes, and ALD could be a novel surface processing method for Ti dental implants in the near future.

Switchable bubble wettability copper mesh for underwater gas collection ablated by spatial modulated femtosecond laser

With the development of energy exploitation and drug researching, people pay more attention on underwater gas collection. Switchable bubble wettability surfaces play an important role in these areas. In this paper, a fast, flexible and efficient switchable bubble wettability copper surface processing method is reported. It is using spatial light modulated femtosecond laser sputtering and ablation, and its processing efficiency has increased several times. The laser treated copper mesh surfaces not only show reversible switching ability between underwater (super-)aerophilicity and superaerophobicity, but also can be cycled many time. Therefore, the as-prepared surface can control bubbles to pass through or block by switching wetting property. Finally, we demonstrated the underwater superaerophobic characteristic of the as-prepared copper mesh was used for gas collection and the gas intrusion pressure of the prepared copper mesh was studied theoretically and experimentally.