Search Results (86)

This study investigates the thermal stability and microstructural evolution of the solid electrolyte medium used in DLyte^® dry electropolishing and dry anodizing processes. Samples were thermally aged between 30 °C and 45 °C to simulate Joule heating during industrial operation. Visual and SEM analyses revealed shape deformation and microcrack formation at temperatures above 40 °C, potentially reducing particle packing efficiency and electrolyte performance. Particle size distribution shifted from bimodal to trimodal upon aging, with an overall size reduction of up to 39.5% due to dehydration effects, impacting ionic transport properties. Weight-loss measurements indicated a diffusion-limited dehydration mechanism, stabilizing at 15–16% mass loss. Fourier transform infrared analysis confirmed water removal while maintaining the essential sulfonic acid groups responsible for ionic conductivity. In dry anodizing tests on titanium, aged electrolytes enhanced process efficiency, producing TiO₂ films with improved optical properties—color and brightness—while preserving thickness and uniformity (~70 nm). The results highlight the need to carefully control thermal exposure to maintain electrolyte integrity and ensure consistent process performance. Full article

Tungsten and tungsten alloys are widely used in important industrial fields due to their high density, hardness, melting point, and corrosion resistance. However, machining often leaves processing marks on their surface, significantly affecting the surface quality of precision components in industrial applications. Electrolytic polishing offers high efficiency, low workpiece wear, and simple processing. In this study, an electrolytic polishing method is adopted and a novel trisodium phosphate–sodium hydroxide electrolytic polishing electrolyte is developed to study the effects of temperature, voltage, polishing time, and solution composition on the surface roughness of a tungsten–nickel–iron alloy. The optimal voltage, temperature, and polishing time are determined to be 15 V, 55 °C, and 35 s, respectively, when the concentrations of trisodium phosphate and sodium hydroxide are 100 g·L⁻¹ and 6 g·L⁻¹. In addition, glycerol is introduced into the electrolyte as an additive. The calculated LUMO value of glycerol is −5.90 eV and the HOMO value is 0.40 eV. Moreover, electron enrichment in the hydroxyl region of glycerol can form an adsorption layer on the surface of the tungsten alloy, inhibit the formation of micro-pits, balance ion diffusion, and thus promote the formation of a smooth surface. At 100 mL·L⁻¹ of glycerol, the roughness of the tungsten–nickel–iron alloy decreases significantly from 1.134 μm to 0.582 μm. The electrochemical polishing mechanism of the tungsten alloy in a trisodium phosphate electrolyte is further investigated and explained according to viscous film theory. This study demonstrates that the trisodium phosphate–sodium hydroxide–glycerol electrolyte is suitable for electropolishing tungsten–nickel–iron alloys. Overall, the results support the application of tungsten–nickel–iron alloy in the electronics, medical, and atomic energy industries. Full article

In electropolishing, the material removal rate is frequently neglected, as this process is primarily focused on surface finish, and yet, it is crucial for manufacturing metallic sheets. Solutions are required to enhance the material removal rate while maintaining surface quality. This work introduces an electropolishing technique that involves suspending ethanol in an electrolyte solution and employing a magnetic field during machining processes. The Taguchi approach is utilized to determine the ideal process parameters for enhancing the material removal rate of SS 316L electropolishing through a L9 orthogonal array. Pareto analysis of variance (ANOVA) is utilized to examine the four parameters of the machining process: applied voltage, ethanol concentration, machining gap variation, and the magnetic field of the electrolyte. The results demonstrate that the applied voltage, the incorporation of ethanol in electropolishing, and a reduced machining gap significantly increase the material removal rate; however, the introduction of a magnetic field did not notably increase the material removal rate. Full article

Nb₃Sn has a superconducting transition temperature of 18.1 K and a superheating magnetic field of 420 mT, making it one of the most promising materials for superconducting radiofrequency (SRF) cavities. The surface roughness reduction and mechanical stability of Nb₃Sn films are two important issues to improve the cavity RF performance and reliability in the application of conduction-cooling accelerators. This paper presents the studies on the surface roughness of Nb₃Sn films prepared by the tin vapor diffusion method and proves the advantages of buffered electropolishing (BEP) as a pre-polishing method. The smallest mean roughness of 26 nm, with a grain size of 760 nm, was achieved by fast BEP treatment on the niobium substrate. Nb₃Sn films on flat and curved substrates with the same coating process on Nb₃Sn cavities at Peking University (PKU) were tested under different tensile and compressive stress levels. The results showed that Nb₃Sn films had severe crack risks while loading stresses, and a safe strain range of (−2.3%, 0.9%) is suggested. To study the tuning problems for Nb₃Sn cavities, 150 kHz tuning was performed on the previously obtained high-performance cavity. Full article

Biomedical alloys in general, except for the biodegradable type, exhibit passive behavior in neutral chloride solutions. Two commonly used biomedical alloys are nitinol (NiTi) and Co-35Ni-20Cr-10Mo (CoNiCrMo). In this work, the passive behavior of electropolished NiTi and CoNiCrMo in a simulated physiological solution (phosphate-buffered saline) was compared using data largely obtained from our previous studies involving potentiodynamic polarization and electrochemical impedance spectroscopy (EIS). The potentiodynamic results showed a marked difference in passive behavior between the alloys, with NiTi remaining completely passive up to the oxidation of water and CoNiCrMo, in contrast, undergoing solid-state oxidation and then transpassive dissolution. Both alloys exhibited Tafel-type behavior over the initial part of the passive range. A small but distinct difference in the apparent Tafel slopes was found between the two alloys and can be attributed to the difference in their predominant oxide; that is, TiO₂ versus Cr₂O₃. The EIS results also showed marked differences between the alloys in terms of the oxide thickness and resistivity. The thickness was greater for NiTi—consistent with surface analytical results—and differed in potential dependence between the two alloys in the passive region. The oxide resistivity, conversely, was substantially lower for NiTi and showed a similar potential dependence for the two alloys. Full article

Mechanically flexible substrates are increasingly utilized in electronics and advanced energy technologies like solar cells and high-temperature superconducting coated conductors (HTS-CCs). These substrates offer advantages, such as large surface areas and reduced manufacturing costs through reel-to-reel processing, but often lack the surface smoothness needed for optimal performance. For HTS-CCs, specific orientation and high crystalline quality are essential, requiring buffer layers to prepare the amorphous substrate for superconductor deposition. Techniques, such as mechanical polishing, electropolishing, and chemical-mechanical polishing, can help achieve an optimally levelled surface suitable for the subsequent steps of sputtering and ion-beam-assisted deposition (IBAD) necessary for texturing. This review examines Solution Deposition Planarization (SDP) as a cost-effective alternative to traditional electro-mechanical polishing for HTS coated conductors. SDP achieves surface roughness levels below 1 nm through multiple oxide layer coatings, offering reduced production costs. Comparative studies demonstrate planarization efficiencies of up to 20%. Ongoing research aims to enhance SDP’s efficiency for industrial applications in CC production. Full article

Austenitic stainless steels are used widely in many fields due to their good mechanical properties and high resistance to corrosion. This work focuses on the reconstruction of the passive film after scratching. The purpose of the study was to compare changes in the rate of passive layer reconstruction and to discuss the effect of both the type of material and its electrochemical treatment on the reconstruction of the passive layer for two types of stainless steel: 304 and 316. The XPS tests performed indicate a significantly higher Cr/Fe ratio for the samples after the electropolishing process of 1.41–1.88 compared to the as-received samples of 0.82–0.86. After 2–3 min of sputtering the surface with Ar+ ions, a decrease in chromium content can be observed, with a simultaneous increase in nickel content, visible especially for the electropolished samples. A new approach in the conducted research was to scratch the test samples under controlled conditions, then evaluate the dynamics of the passive layer reconstruction using the AFM method, and then confront the obtained results with XPS measurements for the corresponding samples. For the as-received samples (2B finish) and those after surface treatment, regardless of the level of contamination of the electropolishing process bath, the reconstruction time was similar, which was approximately 2 h, although certain differences in the process dynamics were noticeable. Full article

This study systematically compares the surface polishing performance and finishing results of the following two different electrolytic plasma polishing technologies on stainless steel AISI 316L: (i) plasma electrolytic polishing (PEP) and (ii) plasma electrolytic polishing jet (PEP-Jet). The two techniques are compared against an industrial standard polishing method, electropolishing (EP). For comparable energy density consumption, the samples treated with the PEP-Jet technique showed the highest removal rate, up to three times less than the initial roughness, resulting in the highest surface roughness reduction from Sa = 249 nm to Sa = 81 nm. Microstructure characterization of samples treated using PEP-Jet also showed well-defined crystalline grain boundaries with a distinct appearance of predominantly inter-crystalline structures within individual grains, which is uncommon with EP techniques. The surfaces treated using PEP-Jet exhibited the lowest corrosion rate of $6.79\times {10}^{-5}$ mm/year, and no signs of areal corrosion were detected in the performed corrosion tests in contrast with the other samples and their respective treatments. The comparative analysis revealed that the high ionic current delivered by the electrolyte jet flow in the PEP-Jet process effectively stabilizes the plasma at the contact zone, thereby enhancing the plasma polishing of austenitic stainless steel samples. The efficacy of this method has been demonstrated in terms of reducing energy consumption and enhancing corrosion resistance in comparison with (PEP) and (EP) as state-of-the-art processes in corrosive environments of high-alloyed steel. Full article

Post-processing, and particularly the dry electropolishing process, is essential for improving the surface quality of 3D-printed Ti6Al4V samples, with specific emphasis on reducing roughness over extended polishing times while preserving mechanical properties. Reducing surface roughness enhances the reliability of hardness measurements and improves the consistency of elastic modulus measurements, as prolonged polishing time stabilizes the full width at half maximum values, thereby minimizing variability due to uniaxial indentation. This stability is crucial for maintaining the structural integrity and uniformity of mechanical properties, facilitating better performance and reliability in biomedical applications. Additionally, under service-like working conditions, solid electrolyte particles undergo dehydration due to the Joule effect, introducing a dynamic aspect to the system as the particle structure degrades with thermal cycling. EDX cross-sectional analysis reveals that TiO₂ informs the particle’s surface, with an oxygen-to-titanium ratio that confirms the oxide’s composition. This TiO₂ oxide layer demonstrates the progressive surface oxidation occurring under the post-processing process, further modifying the particle’s surface chemistry. This dual effect of roughness reduction and controlled surface chemistry highlights the role of dry electropolishing in enhancing the functional lifespan and mechanical reliability of Ti6Al4V components. Full article

Electropolishing using a high-current density results in a pitting phenomenon, producing a surface texture distinguished by many pits. Apart from the change in surface topography, electropolishing forms an oxide surface layer characterized by beneficial tribological properties. This paper introduces surface texturing in worm gear pairs by electropolishing a 16MnCr5 steel worm surface. Electropolishing produces surface pits 1 μm to 5 μm deep and 20 to 100 μm in diameter. The material characterization of 16MnCr5 steel is compared against the electropolished 16MnCr5 steel based on microstructure, hardness, surface topography and chemical composition. Experimental tests with worm pairs employing electropolished worms are conducted, and the results are compared to conventional worm pairs with ground steel worms. Electropolished worms show up to 5.2% higher efficiency ratings than ground ones and contribute to better running-in of worm gear pairs. Moreover, electropolished worms can reliably support full contact patterns and prevent scuffing due to improved lubrication conditions resulting from the produced surface texture and oxide surface layer. Based on the obtained results, electropolishing presents a promising method for surface texturing and modification in machine elements characterized by highly loaded non-conformal contacts and complex geometry. Full article

Electropolishing is a widely used technique for polishing additive manufactured (AM) components, while complex internal surface polishing remains a challenge. In this study, we explore the use of ethaline as an electrolyte and investigate the effects of temperature, time, stirring speed, and voltage on the electropolishing effectiveness for AM tubes without pre-treatment through orthogonal experiments. The optimal combination of these factors is then applied in further electropolishing experiments on straight tubes with large length-to-diameter ratios and an angled tube. Our results indicate that temperature has the most significant impact on internal surface electropolishing performance, and other factors’ effects are also analyzed. Ethaline can be a promising electrolyte for internal surface electropolishing of AM components because of its high viscosity, which is validated by flow field simulation of the hydrodynamic conditions inside the tubes. Full article

Volatile organic compounds (VOCs) play a crucial role in emission control, being one of the most important sources of odor while also serving as significant precursors to secondary organic aerosols and ozone formation. Appropriate sampling methods are essential for accurately assessing the concentration and composition of VOCs within swine barns. In this study, the effects of both passive air sampling and active air sampling on VOCs were evaluated, and the influence of storage time on the VOC stability in sampling canisters for both methods was investigated. SUMMA canisters, which are electropolished and passivated with silanization, offer excellent corrosion protection and resistance to high pressure and temperature and were used in this study. The predominant component categories prevailing within the pig house were found to be oxygenated VOCs (OVOCs) and volatile sulfur compounds (VSCs), with ethanol emerging as the most abundant component of VOCs detected. Notably, the statistical analysis results revealed no significant differences between passive and active sampling regarding the impact of storage time on substance concentration. Changes in canister pressure also did not significantly affect substance stability. The results showed that the C2–C3 compounds remained relatively stable, especially within 3 days, with recoveries above 80% within 20 days. Methyl sulfide, dimethyl disulfide, and ethanol were more stable within the first week, but their recoveries significantly dropped by day 20, with methyl sulfide and dimethyl disulfide at 62.3% and 65.3%, respectively. This study contributes to the development of a foundation for selecting appropriate VOC sampling methods in swine facilities for conducting a rational analysis of VOC samples. Full article

Electropolishing (EP) has become a standard procedure for treating the inner surfaces of superconducting radio-frequency (SRF) cavities composed of pure niobium. In this study, a new EP facility was employed for the surface treatment of both 1.3 GHz and 3.9 GHz single-cell cavities at the Wuxi Platform. The stable “cold EP” mode was successfully implemented on this newly designed EP facility. By integrating the cold EP process with a two-step baking approach, a maximum accelerating gradient exceeding 40 MV/m was achieved in 1.3 GHz single-cell cavities. Additionally, an update to this EP facility involved the design of a special cathode system for small-aperture structures, facilitating the cold EP process for 3.9 GHz single-cell cavities. Ultimately, a maximum accelerating gradient exceeding 25 MV/m was attained in the 3.9 GHz single-cell cavities after undergoing the cold EP treatment. The design and commissioning of the EP device, as well as the electropolishing and vertical test results of the single-cell cavities, will be detailed herein. These methods and experiences are also transferable to multi-cell cavities and elliptical cavities of other frequencies. Full article

Electropolishing is a common treatment in the industry; however, how it behaves in the mouth and what benefits it can bring over metal dental attachments have not yet been established. Thus, the aim of this study was to determine the levels of corrosion, the released metal ions, and the changes in structural composition in metallic orthodontic appliances following electropolishing treatment. This study included 56 orthodontic brackets and 28 archwires. The samples were subjected to a pH cycle to simulate an oral environment. Using UV–Vis spectrophotometry, the release of metallic particles was evaluated, and using scanning electron microscopy, the structural and composition changes were evaluated. Groups were compared using Student’s t-tests with a value of p ≤ 0.05. The cyclical pH solutions showed variations between groups and days (1, 3, 5, 7 and 15), reaching the highest acidification in the self-ligating brackets; the absorbance between solutions did not differ significantly. As seen from the SEM results, the experimental group showed minor irregularities compared with the control groups. The experimental brackets decreased in iron and increased in chromium after electropolishing, while for the NiTi archwires, they decreased in nickel. Therefore, electropolishing treatments in metallic orthodontic attachments improve their surface structure and corrosion resistance could reduce the risk of metal hypersensitivity, mainly from nickel. Full article

This paper reports the results of our study on electrochemical polishing of titanium and a Ti-based alloy using non-aqueous electrolyte. It was shown that electropolishing ensured the removal of surface defects, thereby providing surface smoothing and decreasing surface roughness. The research was conducted using samples made of titanium and Ti₆Al₄V alloy, as well as implant system elements: implant analog, multiunit, and healing screw. Electropolishing was carried out under a constant voltage (10–15 V) with a specified current density. The electrolyte used contained methanol and sulfuric acid. The modified surface was subjected to a thorough analysis regarding its surface morphology, chemical composition, and physicochemical properties. Scanning electron microscope images and profilometer tests of roughness confirmed significantly smoother surfaces after electropolishing. The surface profile analysis of processed samples also yielded satisfactory results, showing less imperfections than before modification. The EDX spectra showed that electropolishing does not have significant influence on the chemical composition of the samples. Full article