Preparation Of Metal Surfaces Research Articles

Features of the Preparation of Metal Surfaces of Machine Parts before Gluing

Features of the Preparation of Metal Surfaces of Machine Parts before Gluing

Injection overmolding of polymer‐metal hybrid structures: A review

AbstractPolymer‐metal hybrid (PMH) structures, also known as metal‐polymer hybrid (MPH) structures, have received considerable attention from industry and academia due to the societal need for developing strong, lightweight, and durable structures for several applications in strategic areas, such as transportation, household appliances, energy, and biomedical devices. Injection overmolding is an advantageous technique for manufacturing PMH structures as it combines automation, a fast process, cost efficiency, and dimensional accuracy. This review presents a comprehensive discussion of recent advances reported in the literature concerning PMH structures fabricated by direct‐adhesion injection overmolding. Following a general introduction, the fundamentals of the injection overmolding technique are presented. Next, the potential of some metal surface preparation methods to ensure good adhesion, and thus outstanding mechanical performance in injection overmolded PMH structures is discussed. Correlations are then made between metal surface features, processing parameters, and the mechanical strength of injection overmolded polymer‐metal joints. Some applications of injection overmolded PMH structures are explored, and, lastly, the main conclusions and prospects on the use of injection overmolding are presented.

Selection of materials for repairing punctures of metal skin of semi-monocoque structures using composite patches

For repairing punctures of skin of semi-monocoque structures under field conditions, simple methods are sought to guarantee the reliability of the repaired structure. Therefore, adhesive joints and composite materials are being increasingly used in repairs. During repairs using adhesion, an important aspect that affects the quality of the joint is the selection of the adhesive and the quality of surface preparation of the parts to be joined. This is necessary to get the right bond strength and durability of the joint in working environments characterized by extreme temperatures and exposure to chemicals and moisture. The purpose of the study was to select an adhesive with good strength properties for bonding AW2024T3 aluminum sheets to carbon and glass composites, and to analyze the effect of metal surface preparation on the strength of adhesive joints (grinding, sandblasting and chemical surface preparation). The tests were carried out on overlap (metal-composite) specimens. For selected adhesives, strength tests were also carried out on specimens replicating the repaired damage with a diameter of 20 mm of metal skin repaired by different methods, including composite patches and adhesive joints. The specimens were loaded in tension and loss of stability. The tests made it possible to determine the requirements for composite patches used for repairing upper and lower airframe wing skins.

The effect of laser surface textures on the corrosion resistance of epoxy coated steel exposed to aggressive environments for offshore applications

Organic coatings are commonly applied to protect metallic structures exposed to highly corrosive environments such as those found in offshore marine scenarios. In general, steel surfaces are prepared by grit blasting prior to being coated. However, this method is associated with some negative issues such as adverse environmental impacts, and safety concerns. In this context, laser surface texturing technology is gaining attention and has been used for metal surface preparation (micromachining, drilling and functionalization) in various applications. This method offers several benefits, notably ease of automation and scalability. This paper reports an investigation on the resistance to corrosion propagation of epoxy-coated laser-textured AISI A-36 surfaces, when compared to surfaces subjected to the conventional bead and grit blasting treatments (references). Nanosecond laser surface texturing was used to create groove-like and grid-like surface patterns at the microscale level. After running accelerated corrosion tests (ISO 12944-9 standard), the performance of the epoxy coating on the laser-textured surfaces was significantly improved, indicating that the laser treatment reduces the coating delamination rate, as well as its damaged area. The surface tortuosity factor plays an important role in the effectiveness of the coatings. The results also suggest that the geometrical aspects of the groove structure (presence of recast material and V-shape) promote phenomena such as mechanical interlock and mechanical hooking of the coating. Therefore, nanosecond laser surface texturing appears to be a suitable procedure for the preparation of steel surfaces installed in offshore marine environments.

Influence of Sandblasting and Chemical Etching on Titanium 99.2-Dental Porcelain Bond Strength.

The metal–ceramic interface requires proper surface preparation of both metal and ceramic substrates. This process is complicated by the differences in chemical bonds and physicochemical properties that characterise the two materials. However, adequate bond strength at the interface and phase composition of the titanium-bioceramics system is essential for the durability of dental implants and improving the substrates’ functional properties. In this paper, the authors present the results of a study determining the effect of mechanical and chemical surface treatment (sandblasting and etching) on the strength and quality of the titanium-low-fusing dental porcelain bond. To evaluate the strength of the metal-ceramic interface, the authors performed mechanical tests (three-point bending) according to EN ISO 9693 standard, microscopic observations (SEM-EDS), and Raman spectroscopy studies. The results showed that depending on the chemical etching medium used, different bond strength values and failure mechanisms of the metal-ceramic system were observed. The analyzed samples met the requirements of EN ISO 9693 for metal-ceramic systems and received strength values above 25 MPa. Higher joint strength was obtained for the samples after sandblasting and chemical etching compared to the samples subjected only to sandblasting.

Application of organosilanes in the preparation of metal surfaces for adhesive bonding

This paper deals with research into the influence of surface preparation before adhesive bonding of galvanised and non-galvanised steel substrates. The steel substrates were experimentally treated with chromate-free zirconate passivation, iron phosphate, zinc phosphate and an experimental organosilane-based preparation. The roughness of the treated substrates was evaluated by a set of selected vertical and horizontal parameters. The corrosion rate of the treated substrates was tested by electrochemical impedance spectroscopy and linear polarisation. Single-lap joints were created using one-component epoxy/PVC-polymerblend adhesive with glass beads, to ensure an evenly glued gap. The joints were tested for shear strength by tension, in accordance with STN EN 1465 in the as-bonded state, as well as after the climatic cyclic test PV1200. The results show that the adhesive used had a higher adhesion to galvanised substrates with a specific morphology. Adhesion to non-galvanised substrates has been significantly improved by using organosilane for surface preparation. The organosilane layer, containing epoxy organic functional groups, was incorporated into the organic binder of the adhesive and showed increased bond strength.

Controllable superwettability of Cu mesh by one-step immersion in fatty acids with different carbon chain lengths

The preparation of superhydrophobic metal surfaces by one-step immersion in fatty acid solutions is simple and convenient, but the effect of the fatty acid type has not been investigated. In this work, Cu meshes were soaked in ethanol solutions of fatty acids with different carbon chain lengths to obtain surfaces with different wettabilities, which varied from superhydrophilicity to superhydrophobicity. The results showed that the contact angle of the surfaces gradually increased from 2.7 ° for the sample prepared with formic acid to 151.8 ° for the sample prepared with myristic acid. The maximum apparent surface energy and solubility parameter were 82.33 mN/m and 65.79 J1/2/cm3/2 for the C1-Cu surface, and the lowest were only 6.3 mN/m and 19.91 J1/2/cm3/2, respectively, for C14-Cu. A simulation confirmed that as the carbon chain length of the fatty acid increased, the solubility parameter decreased, and the hydrophobicity increased. One-step immersion enables facile, inexpensive one-step preparation of membrane surfaces with controllable superhydrophobicity for large-scale industrial applications.

Influence of metal surface preparation on the flexural strength and impact damage behaviour of thermoplastic FRP reinforced metal laminate made by press forming

In this paper the relationship between surface energy and flexural strength of metal laminate made by reinforcing glass fibre reinforced polymer on steel surfaces was investigated. Sand blasting was performed on 22MnB5 steel surface. This steel was stacked together with layers of unidirectional glass/polyamide-6 prepreg, followed by pressing in a hot press. Influenced parameters are pressure, temperature and time. 3D profilometer analysis was used to investigate the roughness profile on the surface of the steel generated by the sand blasting. The surface energy of the steel surface was calculated from a set of contact angles measured by three different liquids. To identify the optimal surface treatment, the variation of surface energy, flexural strength and roughness of the steel surface was determined as function of the surface treatment. Surface roughness (Ra of 1.08 μm), results indicate that increasing surface roughness leads to improvement in flexural modulus. The increase further leads to decrease in flexural modulus. In addition, the influence of surface energy and flexural strength on the impact damage behaviour was investigated too. The results showed that the sample with highest flexural modulus had the lowest impact-induced damage area.

Pretreatment effect of the pure titanium surface on hybrid coating adhesion based on tetraethoxysilane and methyltriethoxysilane

Hybrid coatings based on silicon alkoxide precursors are one of the options for coating metal surface biomaterials such as pure titanium (Ti). However, the nature and the metal surface preparation, before the coating application, are of fundamental importance for perfecting the coating/surface adhesion. In this study, three different pretreatments were used for the Ti surface: Kroll, Piranha and NaOH. After the pretreatment, the coating was applied by the dip-coating process, using the sol–gel method from the silicon alkoxide precursors, tetraethoxysilane and methyltriethoxysilane. The results of thermogravimetric analysis showed that the tested coatings had excellent thermal stability. The pretreatment with NaOH solution increased the surface roughness of the Ti, thus modifying its surface energy and increasing its wettability. Field emission scanning electron microscopy showed a homogeneous coating with good adhesion of the hybrid coating to the Ti surface, and higher layer thickness on the surface treated with NaOH. In addition, its electrochemical performance was better than the surfaces pretreated with acids.

Selection of Conversion Layer Applied Beneath Thread Lubricant Coating

A polymer coating is often used instead of lubricant in order to protect the threaded part of an oil pipe fitting. There are several forms of these coatings of different composition applied by spraying to the threaded element of a pipe. Metal surface preparation before coating application has a considerable effect on polymer coating quality. Conversion coatings that formed on a pipe threaded surface and couplings as an intermediate layer between a metal surface and a polymer coatings are analyzed. The conversion coatings selected are various phosphate coatings and an alternative phosphate-free zirconium coating. Comparative study of these coatings includes an analysis of application technology, a study of conversion coatings physicochemical properties, and comparative tests for a conversion coating – thread lubricant coating system.

ELECTROLYTIC PLASMA POLISHING OF COPPER

Modern industrial technological processes require special preparation of metal surfaces. Currently, there are different methods of surface treatment of metal. Among them, it is possible to distinguish the method of electrolytic-plasma polishing (PEP– plasma electrolytic polishing) is distinguished as an innovative, due to its ecological properties, low energy consumption per unit of surface to be processed, high speed of modification and the possibility of processing parts of complex geometric shape. The main advantage of this method of surface modification is its ecological purity, which makes it possible to apply this technology to the food and pharmaceutical industry. Despite the large number of journal publications, electrolytic plasma polishing remains an innovative surface modification method that needs to be thoroughly studied in order to improve understanding of physical processes and optimize the surface modification process. The process of obtaining electrolytic plasma polishing of copper products in a solution of ammonium sulfate with the addition of sulfuric acid is considered in the paper. The experiment was divided into two stages. At first, the samples were treated for 600 seconds each for the obtain of temperature characteristics, with a strong correlation between the load current and the electrolyte temperature was observed. Dependence of the current on the temperature of the electrolyte showed four different modes of treatment. One of the modes showed the best results. During the second series of experiments, the processing of objects from 30 to 600 seconds. As a result of the conducted studies, optimal regimes for polishing copper objects were obtained.

Preparation of metal surfaces for application of functional coatings

This paper proposes an efficient method of plasma purification of metal surfaces before applying coatings or the product finishing treatment. The plasma purification is performed in a steam-gas discharge with an aluminum anode and a liquid cathode.

Research of Physical Mechanical and Protective Properties of the Lignin Rust Modifier

In the given article, the data on preparation of metal surface at anticorrosive protection by paintwork materials are given. Conducted research on water absorption and protective properties of the lignin rust modifier in various hostile environment was carried out. There is shown high anticorrosive efficiency of the developed lignin rust modifiers which will be used for preparation under coloring of steel surfaces with the aim of transforming corrosion products to chemical permanent water insoluble connections which are strongly connected with metal surface.

Influence of metal surface preparation on its surface profile, contact angle, surface energy and adhesion with glass fibre prepreg

Surface preparation of metal plays a vital role to enhance the adhesion of polymer coatings in ensuring the desired performance of metal infrastructure for the oil and gas industry. In this study, a range of techniques for the surface preparation of mild steel were evaluated which included garnet grit blasting, disk sanding, needle gun, flap wheel, strip wheel and wire brush. The surface profile and apparent surface energy parameters such as apparent surface energy, work of adhesion, Lifshitz-van der Waals acid–base components were measured from these trials correlation made with these properties to the metal to polymer coating bond strength and bond failure mode.The dolly pull-off strength was used to quantify the bond strength while the laminate failure area (%) was used to assess the bond failure mode. Based on the testing results, it was found that irrespective of the surface preparation technique used, the dolly pull-off strength and laminate failure area increased with increasing surface profile up to a value of approximately 21µm and both of these properties followed a plateau up to 24μm and then decreased above this surface profile value. The dolly pull-off strength was also seen to increase with the increase of surface energy and work of adhesion and decrease of contact angle. It was found that the maximum adhesion could be attained with three of the four grit sizes of the garnet grit blasting technique which appeared to have achieved the most favourable properties amongst all the surface properties studied here. Wenzel model was found to be in agreement with the values of the surface profile of different surface preparation techniques.

Effect of Different Substrate Pre-Treatments on the Resistance of Aluminum Joints to Moist Environments

The goal of this work was to evaluate and compare the performance of different surface pre-treatments applied to aluminium single lap joints exposed to warm moisture. Four different processes were considered: 1) degreasing-roughening; 2) degreasing-roughening and phosphoric acid anodising; 3) degreasing-roughening and conditioning with Picklex®20 (a water-based product for metal surface preparation); 4) degreasing-roughening and phosphoric acid anodising and contaminating the adherend surface with CaCl2 to accelerate the tests. After each pre-treatment, lap-shear specimens were prepared with the open face technique. The half-joints were exposed to warm moisture (50°C, 100% RH) for times up to 4 weeks, then they were completed and subjected to mechanical testing. The results show that anodising yields the best durability, as strength remained practically constant over time; all the other groups of specimens exhibited progressive reduction in strength and wider scatter of the results. A large role is played by interfacial damage of the adherends, since, under increasing exposure time, failure tends to occur as separation at the adhesive-metal interface. The strength decreased dramatically also for the anodised specimens when the surface was contaminated, which evidences the role of the interfacial damage. The interpretation is supported also by scanning electronic microscopy observation and energy-dispersive X-ray analysis.

Application of thin metal film elements in bioanalysis

Advanced metal deposition and microfabrication techniques enable preparation of metal surfaces with high precision and excellent control over their size and shape with subnanometer resolution. Thin metal films of different types and functions can be found in many analytical instruments. Surfaces with high optical quality serve as mirrors, beam splitters, antireflective coatings etc. Smooth metal coating is crucial in electron microscopy. Unique properties of the thin metal films are widely used in optical systems, as tools for sample manipulation but also for chemical sensing and detection. While some of the applications are widespread and belong to the basic curriculum in analytical chemistry, the newer or less common uses of thin metal films are well known only to the experts in the field. The purpose of this critical review is to highlight the role of thin metal films in bioanalysis and summarize some of their main applications in current bioanalytical instrumentation.

Color change during the surface preparation stages of metal ceramic alloys

Even though metal ceramic restorations (MCRs) are widely used by clinicians, the influence of the metal on the color of overlaying porcelain is unknown. The purpose of this study was to analyze the color alterations of different types of metal ceramic alloys during several stages of metal surface preparation and to determine the effect of those changes on the resulting color of opaque porcelain (OP). Seven different types of alloys (3 base metal, 3 noble, and 1 high noble) were used to prepare disk-shaped specimens (1 mm × 10 mm, n=3), followed by OP application (0.1 mm). L*a*b* values of specimens were recorded after different stages of metal surface preparation (ingot, after casting, after oxidation, and after the OP application) in addition to the shade tab of OP B1 (target shade). L*a*b* values of alloys were measured from the ingot structure to the OP application stage and statistically analyzed (Repeated measures ANOVA, and Bonferroni corrected paired t test, α=.05). L*a*b* values of OP applied groups and the OP shade tab (target shade) were analyzed (1-way ANOVA with Dunnett's multiple comparison test, α=.05). The color differences of the target shade both before and after OP application were calculated and statistically analyzed (1-way ANOVA, Ryan-Einot-Gabriel-Welsch Multiple Range Test, α=.05). The L* values of all alloys changed significantly after each stage except for 2 alloys (V-Deltaloy SF (N-VDSF)) and (Gnathos Plus (HN-GP)) after casting and airborne-particle abrasion (P<.05). The a* value of all alloys increased after casting. Changes in the a* coordinate were significant except for one of the base metal alloys (P<.05). The a* coordinate changes of alloys showed variation in direction after oxidation and OP application (P<.05). The b* coordinate changes of alloys showed variation in direction after each stage (P<.05). The L*a*b* values of some OP applied alloys were significantly different from that of the OP shade tab (P<.05). Color difference values (ΔE (OP applied alloy-target shade)) of 2 OP-applied alloys (Cerapall 2 (N-CP2) and Ceradelta (N-CD)) were significantly different (P<.05) and higher than the other OP-applied alloys. The achromatic color behavior of different alloys was all in the same direction at all metal surface preparation stages. The chromatic behavior of the different alloys was primarily towards the same direction after casting and airborne-particle abrasion, whereas it varied after oxidation and OP application. The color difference of OP for all alloys, regardless of their type, was not visually perceivable when compared to the target shade (ΔE<2.6).

Measurement method for carrier concentration in TiO 2 via the Mott–Schottky approach

In direct contrast to the way in which silicon is precisely doped for integrated circuit applications in order to optimize device performance, there is little nuanced understanding of the correlation between TiO 2 doping level, charge carrier concentration, and the operation of TiO 2-based photocatalysts, dye-sensitized solar cells, and sensors. The present work outlines a rigorous methodology for the determination of free carrier concentration for doped metal oxide semiconductors such as TiO 2 that are not amenable to standard metrology methods. Undoped, Cr-, Mn-, and Nb-doped polycrystalline anatase TiO 2 are synthesized via atomic layer deposition (ALD) using Ti(OCH(CH 3) 2) 4, H 2O, Cr(C 5H 7O 2) 3, Mn(DPM) 3 (DPM = 2,2,6,6-tetramethyl-3, 5-heptanedionato), and Nb(OCH 2CH 3) 5 as the source materials for Ti, O, Cr, Mn, and Nb, respectively. Chemical composition and crystallinity are investigated and a thorough “device-like” characterization of TiO 2 Schottky diodes is carried out to justify the subsequent extraction of carrier concentration values from capacitance–voltage (C–V) measurements using the Mott–Schottky approach. The influence of factors such as substrate type, contact metal type, and surface and interface preparation are examined. Measurements of donor carrier concentration are obtained for undoped, Cr-, Mn-, and Nb-doped TiO 2 synthesized by ALD. Possible causes for the obtained carrier concentrations are discussed.

Metal Surface Preparation for Wafer Bonding with Point of Use Wet Chemistries

Diffusion and eutectic bonding are gaining broad acceptance in 3D integration and packaging. Many bonding schemes are based on copper because this material is used extensively in FEOL, has a well developed CMP history and high yield TSV's have been proven. One of the issues for low resistivity interconnects and high bonding yield is the surface cleaning methods used to remove copper oxidation. This paper will present the results of studies using DuPont EKC products for copper surface preparation prior to wafer bonding.

Metal Surface Preparation with Point of Use Wet Chemistry

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