Single Surface Treatment Research Articles

Study on Bonding Characteristics of Aluminum Alloy Treated by Plasma Electrolytic Oxidation Process and Polymer Resin Bonded by Direct Injection Molding

Aluminum alloy and polymer resin hybrid bonding technology is essential for lightweight mobile phone frames and automotive components. Recently, there has been extensive research on a method of bonding metals and polymer resins by treating the metal surface and then direct injection molding. However, this method requires separate surface treatment of the aluminum alloy after bonding to enhance its corrosion resistance. This paper studies the use of Plasma Electrolytic Oxidation, one of the surface treatment methods for aluminum, to achieve the bonding of aluminum and polymer resin in a single surface treatment step while ensuring high corrosion resistance. We conducted research to investigate optimal conditions by adjusting the process variables of Plasma Electrolytic Oxidation, in order to achieve integration with the polymer resin and measure the bonding strength and corrosion resistance. The surface characteristics of each Plasma Electrolytic Oxidation condition were analyzed using scanning electron microscopy and atomic force microscope equipment, while the bonding strength was measured using universal testing machine equipment. The corrosion characteristics were evaluated by measuring the corrosion resistance in a saltwater solution.

The effect of surface modification strategies on biological activity of titanium implant

The surface morphology of titanium metal is an important factor affecting its hydrophilicity and biocompatibility, and exploring the surface treatment strategy of titanium metal is an important way to improve its biocompatibility . In this study , titanium (TA4) was firstly treated by large particle sand blasting and acid etching (SLA) technology, and then the obtained SLA-TA4 was treated by single surface treatments such as alkali-heat, ultraviolet light and plasma bombardment. According to the experimental results, alkali-heat treatment is the best treatment method to improve and maintain surface hydrophilicity of titanium. Then, the nanowire network morphology of titanium surface and its biological property, formed by further surface treatments on the basis of alkali-heat treatment, were investigated. Through the cell adhesion experiment of mouse embryonic osteoblast cells (MC3T3-E1), the ability of titanium material to support cell adhesion and cell spreading was investigated after different surface treatments. The mechanism of biological activity difference of titanium surface formed by different surface treatments was investigated according to the contact angle, pit depth and roughness of the titanium sheet surface. The results showed that the SLA-TA4 titanium sheet after a treatment of alkali heat for 10 h and ultraviolet irradiation for 1 h has the best biological activity and stability. From the perspective of improving surface bioactivity of medical devices, this study has important reference value for relevant researches on surface treatment of titanium implantable medical devices.

Review of the surface treatment process for the adhesive matrix of composite materials

To deepen the research on the surface treatment technology of bonding matrix of composite materials, carbon fiber reinforced polymer (CFRP) was selected as the research object, and the research status at home and abroad were reviewed from three aspects: matrix characteristics, durability and bonding and stripping effect before and after surface treatment. Because of the effects of existing surface treatments on the surface roughness, surface wettability, surface morphology, fatigue characteristics, shear strength, and tensile section morphology of CFRP, the influence mechanism of surface treatments on the bonding properties of CFRP was summarized, and the future research focus and direction prospected. The results show that the bonding effect depends on the good mechanical interlocking and adsorption/chemical bonding between the adhesive and CFRP surface. The surface treatment can remove the surface pollutants of CFRP, optimize the surface topography characteristics, and enhance the spreading ability of the adhesive on the substrate surface, thereby enhancing the bonding ability between CFRP and the adhesive. The combination of different surface treatments can significantly improve the preparation quality of the CFRP surface, and avoid the defects of the single surface treatment itself to a certain extent. The surface treatment technology of the bonding matrix is developing in the direction of precision, refinement, and accuracy.

Combining topography and peptide to inhibit algae attachment: Preparation of peptide‐modified microstructured surfaces

Marine facilities and ships are easily plagued by biofouling. Synergistic surfaces combining surface reactive ion etching and peptide modification were designed and prepared to tackle surface biofouling. Six microstructural surfaces were first designed and machined based on the contact point theory; the synergistic surfaces were then prepared by peptide modification. Laser confocal scanning microscope (LCSM), scanning electron microscopy (SEM), contact angle measurement, and X‐ray photoelectron spectroscopy (XPS) were utilized to analyze the surface morphology and surface chemical properties; the results demonstrated that six synergistic surfaces were prepared successfully with 0.8‐μm depth, surface contact angle increased from 75° to 116.99°, and the surface chemical compositions were also changed significantly due to peptide modification. Antibiofilm assays showed that surface modification and surface topology could slightly reduce the formation of biofilm. While the synergistic surfaces possess strong anti‐algal performance, and anti‐Chlorella pyrenoidosa (C. pyrenoidosa) and anti‐Phaeodactylum tricornutum (P. tricornutum) rates reached 78.56% and 87.80%, respectively after 7‐day immersion in artificial seawater. Compared with the single surface treatment method, the antifouling performance of the synergetic surfaces were stronger. This strategy demonstrated a realistic paradigm for the further improving surface antifouling performance in a green method.

Enhancing tribological performance by anodizing micro-textured surfaces with nano-MoS2 coatings prepared on aluminum-silicon alloys

Abstract Aluminum-silicon alloys exhibit poor tribological performance and suffer from severe adhesive wear. The single surface treatment has demonstrated unsatisfactory anti-friction performances. In this paper, the synergistic effect of the surface micro-texturing and nano-solid lubricant improved the tribological performance of aluminum-silicon alloys effectively. The anodizing micro-textured surface with nano-MoS2 coatings was fabricated by micro-milling, anodizing and ultrasonic impregnation. Pin-on-disc tribological tests revealed that the friction coefficient of the anodizing micro-textured surface with nano-MoS2 coatings decreased by 22.6% compared with that of the untextured specimen. The anti-friction characteristic was attributed to the synergistic effect of the entrapping wear debris of dimple structure, the high hardness of porous anodic aluminum oxide films and the self-lubricating property of nano-MoS2 coatings.

Heat transfer model of dropwise condensation and experimental validation for surface with coating and groove at low pressure

It is well known that dropwise condensation corresponds to a high heat transfer coefficient. The high performance enhancement of dropwise condensation in comparison to filmwise condensation is attributed to the ability of non-wetting droplets to be shed from the surface by gravity, therefore reducing the overall thermal resistance. The common treatments to carry out the hydrophobic surface for dropwise condensation are coating and structure. The improvement of heat transfer efficiency by combination of surface treatments with coating and groove structure has been proved compared of surface with single surface treatment by coating or groove structure. Based on this result, in this study presents a model developed to predict the heat transfer efficiency of dropwise condensation for surface with coating and groove structure features. The model is established by heat transfer though a single droplet with the drop size distribution. The heat transfer of single drop is not only analyzed as combination of thermal resistances, but also considered capillary effect of droplet due to groove geometry and properties of surface. In addition, the model results are validated with experimental data which is investigated by varied modification of vapor side metallic surface properties at low absolute pressure. It can be a reference to design industrial condensers of heat exchangers in the future. Further to optimize the surface properties and improve the higher heat transfer performance of dropwise condensation.

Effect of combined shot-peening and PEO treatment on fatigue life of 2024 Al alloy

One of the most important objectives in the surface engineering of light-weight alloys is to enhance their fatigue properties, allowing both increased performance and an extended service life. This can be achieved by forming a hard surface layer while incorporating a favourable stress state. Single surface treatments, for example, Plasma Electrolytic Oxidation (PEO), are not always capable of creating optimal combinations of these characteristics, whereas greater durability can be achieved by applying mechanical pre-treatments prior to the coating. In this work, a combination of shot-peening pre-treatment with plasma electrolytic oxidation coating is studied as a means to improve the fatigue performance of 2024 T351 Al alloy. The shot-peening was carried out in a compressed air configuration using S110 gauge shot at 200% coverage with an intensity of 20 AlmenC. PEO coatings of 30 μm thickness were produced using pulsed bipolar current technology. Fatigue properties were evaluated by a four-point bending technique at a stress ratio of 0.1. Hardness, residual stress and microstructure of the surface layers were studied by Knoop microhardness tests, fluorescence spectroscopy and SEM analyses, respectively. The effect of the combined shot-peening and PEO treatment is an increased fatigue limit and elevated microhardness when compared to aluminium treated only with PEO.

A study into effects of CO2 laser melting of nitrided Ti-6Al-4V alloy

Multiple treatment of engineering surfaces can provide improved surface properties that cannot be obtained by a single surface treatment. Consequently, this study investigates the effects of laser melting on the microstructures of plasma nitrided Ti-6Al-4V alloy. The study consists of two parts. In the first part, governing equations pertinent to the laser melting process are developed, and temperature variation across the melted zone is predicted. In the second, an experiment is conducted to nitride the surface of the alloy through plasma nitriding process and to melt the plasma nitrided and the untreated alloy surfaces with a CO2 laser beam. The resulting metallurgical changes are examined using x-ray diffraction (XRD), bdenergy-dispersive spectrometry (EDS), and scanning electron microscopy (SEM) techniques. It is shown that three distinct nitride layers are formed in the vicinity of the alloy surface prior to the laser melting process, and that after the melting process nitrided species are depleted while cellular and dendritic structures are formed. In addition, the structure consisting of transformed β containing coarse and fine acicular α is observed in the melted regions.

On the reliability of a reasonable single surface treatment of the reaction C +( 2P)+H 2(X 1Σ g+)→CH + +H at relative energies from the threshold region up to 2.0 eV

The dynamics of the C + ( 2P) + H 2 (D 2,HD)→CH + (CD +) + H (D) ion-molecule reaction, at relative energies not far from the threshold (0.4–2.0 eV), has been studied by means of the quasiclassical trajectory method, using a reasonable potential energy surface model derived from both experimental and theoretical information from the literature. Comparison of trajectory results with experimental data shows quite a good accord, disregarding the absolute value of the reactive cross section, which is lower than the experimental one, and the contributions of channels CH + +D and CD + +H to the overall reactive cross section of C ++HD.

Dynamics of the O +( 4S)+H 2(X 1Σ g+)→OH + + H Ion-molecule reaction and some of its isotopic variants (D 2 and HD). II. Quasiclassical trajectory study in the range of relative energies 0.25–6.30 eV

The reaction dynamics of the O +( 4S)+H 2 system and several isotopes (D 2 and HD) have been investigated following the quasiclassical trajectory approach, employing a LEPS + IDI empirical surface derived by us previously from experimental and ab initio information. The properties analysed can be adequately interpreted on the basis of the main topological features of the potential energy surface (PES) used, and comparison of theoretical results with experimental data shows quite good accord, with the only exception of the total cross sections at relative energies above 1 eV which are higher than the experimental ones. Because of the approximate nature of the calculations quantitative agreement with the experiment should not be expected. However, this single surface treatment of the O ++H 2 reaction dynamics leads to reasonably good agreement with the experimental information available.