Conventional Surface Treatments Research Articles

Development of a Superhydrophobic Protection Mechanism and Coating Materials for Cement Concrete Surfaces.

In order to further enhance the erosion resistance of cement concrete pavement materials, this study constructed an apparent rough hydrophobic structure layer by spraying a micro-nano substrate coating on the surface layer of the cement concrete pavement. This was followed by a secondary spray of a hydroxy-silicone oil-modified epoxy resin and a low surface energy-modified substance paste, which combine to form a superhydrophobic coating. The hydrophobic mechanism of the coating was then analysed. Firstly, the effects of different types and ratios of micro-nano substrates on the apparent morphology and hydrophobic performance of the rough structure layer were explored through contact angle testing and scanning electron microscopy (SEM). Subsequently, Fourier transform infrared spectroscopy and permeation gel chromatography were employed to ascertain the optimal modification ratio, temperature, and reaction mechanism of hydroxy-silicone oil with E51 type epoxy resin. Additionally, the mechanical properties of the modified epoxy resin-low surface energy-modified substance paste were evaluated through tensile tests. Finally, the erosion resistance of the superhydrophobic coating was tested under a range of conditions, including acidic, alkaline, de-icer, UV ageing, freeze-thaw cycles and wet wheel wear. The results demonstrate that relying solely on the rough structure of the concrete surface makes it challenging to achieve superhydrophobic performance. A rough structure layer constructed with diamond micropowder and hydrophobic nano-silica is less prone to cracking and can form more "air chamber" structures on the surface, with better wear resistance and hydrophobic performance. The ring-opening reaction products that occur during the preparation of modified epoxy resin will severely affect its mechanical strength after curing. Controlling the reaction temperature and reactant ratio can effectively push the modification reaction of epoxy resin through dehydration condensation, which produces more grafted polymer. It is noteworthy that the grafted polymer content is positively correlated with the hydrophobicity of the modified epoxy resin. The superhydrophobic coating exhibited enhanced erosion resistance (based on hydrochloric acid), UV ageing resistance, abrasion resistance, and freeze-thaw damage resistance to de-icers by 19.41%, 18.36%, 43.17% and 87.47%, respectively, in comparison to the conventional silane-based surface treatment.

Evaluation of shear bond strength of labial veneers after sandblasting/micro-abrasion of prepared teeth by aluminum oxide particles. An in-vitro study

ObjectivesTo explore the feasibility and effectiveness of using sandblasting with aluminum oxide particles to improve the shear bond strength of labial veneer restorations in dentistry. Materials and MethodsA sample size of 50 extracted teeth was divided into five groups, with each group containing ten teeth (n = 10) subject to different treatment protocols. Group 1the control group, underwent conventional surface treatment for labial veneer restorations, including the application of phosphoric acid etchant and bonding protocols. Groups 2 and 3 underwent micro-abrasion using aluminum oxide particles alone for durations of 30 and 45 s, respectively. Groups 4 and 5 experienced a combined approach of micro-abrasion for 30 and 45 s, respectively, followed by conventional surface treatment. The shear bond strength test was performed on each specimen. The resulting modes of failure and surface characteristics were then examined under a digital microscope.The data was analyzed statistically using a one-way analysis of variance (ANOVA) and a post hoc test. ResultsSignificant differences were observed in shear bond strength among the five groups (p < 0.05). The group that underwent conventional + 45-second micro-abrasion treatment exhibited the highest mean shear bond strength (25.69 MPa), while the conventional (controlled) group had the lowest (9.01 MPa). ConclusionFusing sandblasting and aluminum oxide particles could improve the bond strength of labial veneer restorations. Yet, more research is needed to refine this technique for practical application. This includes a broad array of cement types, particle sizes, and clinical situations to ensure the long-term success of veneer restorations.

Approach to Low Contact Resistance Formation on Buried Interface in Oxide Thin-Film Transistors: Utilization of Palladium-Mediated Hydrogen Pathway.

Amorphous oxide semiconductors (AOSs) with low off-currents and processing temperatures offer promising alternative materials for next-generation high-density memory devices. The complex vertical stacking process of memory devices significantly increases the probability of encountering internal contact issues. Conventional surface treatment methods developed for planar devices necessitate efficient approaches to eliminate contact issues at deep internal interfaces in the nanoscale complex structures of AOS devices. In this work, we report the pioneering use of palladium thin film as a high-efficiency active hydrogen transfer pathway from the outside to the internal contact interface via low-temperature postannealing in the H2 atmosphere, and the formation of highly conductive metallic interlayer effectively solves the contact issues at the deeply buried interfaces in devices. The application of this method reduced the contact resistance of Pd electrodes/amorphous indium-gallium-zinc oxide (a-IGZO) thin-film by 2 orders of magnitude, and thereby the mobility of thin-film transistor was increased from 3.2 cm2 V-1 s-1 to nearly 20 cm2 V-1 s-1, preserving an excellent bias stress stability. This technology has wide applicability for the solution of contact resistance issues in oxide semiconductor devices with complex architectures.

Investigation on the physical origins of laser effects on anisotropic magnetic properties of GO electrical steels by means of thermal annealing

Both conventional laser surface treatments (irradiation or scribing) and recently developed ablation process performed with UltraShort Pulse Lasers (USPL) can improve magnetic properties of Grain-Oriented Electrical Steels (GOES) along their Rolling Direction (RD). While pushing the study of laser treatments further, interesting power loss reductions could also be obtained along the Transverse Direction (TD) (or other directions) of GOES using the ablation process with adapted laser patterns. To better understand the physical origins of loss reductions obtained with the USPL ablation process, the effects of a thermal annealing on GOES laser treated with various patterns are investigated. Results differ depending on the excitation direction and in connection with the applied laser treatment and pattern, which provides an original insight into the origins of the modifications of magnetic properties by laser.

A Critical Review of Anti-Corrosion Chemical Surface Treatment of Aluminum Alloys Used for Sports Equipment

Aluminum alloys with low-weight property are promising structure materials for sports equipment. Alloying element-rich second-phase particles create the risk of localized corrosion and result in failure of sports equipment. Chromate conversion coatings as conventional and successful surface treatments were employed to provide a thin but compact film against corrosion. However, chromate species were toxic and carcinogenic for human beings and this process has been highly restricted. In this sense, alternative processes such as trivalent chromium conversion coating with low environmental risk require better corrosion-resistant performance compared to chromate conversion coating. In addition, the closed-loop system of the chromate electroplating process has been used in Europe and the United States. This is also a sustainable process for surface treatment of aluminum alloys applied in sports equipment. The present paper aims to summarize the methods and types of different aluminum alloy surface treatments and compiles the effects of various surface treatments on the corrosion resistance of aluminum alloys. The eco-friendly application of aluminum alloys in the field of sports equipment may be facilitated in the future.

Biologicalisation of surface structuring: Comparative environmental assessment of microbial biomachining vs. chemical etching

In 2015, the United Nations adopted the 2030 Agenda for Sustainable Development in response to growing global concern about climate change, resource scarcity and environmental impacts on ecosystems. This agenda also places high demands on industrial manufacturing systems to promote sustainability. Biologicalisation of manufacturing processes can be a promising approach to contribute to the sustainability goals in industrial production systems. In recent years, biomachining has emerged as a field of research in biologicalisation with potential advantages compared to conventional surface treatment methods of metals, such as chemical etching. Surface structuring of metals plays a crucial role in various industrial applications, such as pre-coating preparation, hierarchical structuring, superhydrophobic surfaces and geometries. To assess the environmental impacts of biomachining, this paper focuses on environmental impacts of utilizing the bacterium Acidithiobacillus ferrooxidans compared to a conventional chemical etching process with cupric chloride solution for surface structuring of a metal specimen. The study examines the environmental impact of both processes, considering all relevant material and energy flows from cradle to gate for multiple environmental impact categories. In doing so, the environmental impacts of each process can be comprehensively evaluated and compared, and hotspots for future improvement of the biomachining process can be identified. On current lab-scale, the results indicate higher impacts for the biomachining process in most categories compared to the chemical etching process, mainly due to the energy demand for pre-cultivation and preparation of the biomachining solution.

Perspectives on Developing Burn Resistant Titanium Based Coatings-An Opportunity for Cold Spraying.

Titanium alloys are crucial lightweight materials; however, they are susceptible to spontaneous combustion under high-temperature and high-pressure conditions, limiting their widespread use in aerospace engines. Improving the burn resistance of Ti alloys is essential for the structural safety and lightweight of aerospace equipment. Burn-resistant Ti alloys, such as Ti-V-Cr and Ti-Cu, however, face limitations such as high cost and low specific strength. Surface coatings provide a cost-effective solution while maintaining the high specific strength and good processability of the base material. Conventional surface treatments, such as laser cladding, result in defects and deformation of thin-walled parts. Cold spray technology offers a promising solution, as it uses kinetic energy to deposit coatings at low temperatures, avoiding defects and deformation. In this paper, we review the current research on burn-resistant surface technologies of Ti alloys and propose a new method of bimetallic coating by cold spraying and low-temperature heat treatment, which has the potential to solve the problem of spontaneous combustion of aerospace engine parts. The strategy presented can also guide the development of high-performance intermetallic compound-strengthened metal matrix composite coatings.

Evaluation paste removal method and bond strength between resin cement and lithium disilicate ceramic: An in vitro study

Statement of problemAfter the use of evaluation paste, residue can remain on the bonding surface. However, how adhesion to lithium disilicate ceramic is affected is unclear. PurposeThe purpose of this in vitro study was to determine the effectiveness of lithium disilicate cleaning after contamination with an evaluation paste and before the application of a resin cement. Material and methodsRectangular lithium disilicate (IPS e.max CAD) specimens were obtained with a simulated milled surface, crystallized, etched with 5% hydrofluoric (HF) acid, and contaminated with an evaluation paste. The cleaning methods tested were air-water spray (SPRAY), 37% phosphoric acid (HPO), ultrasonic bath (ULT), cleaning paste (IVOC), and a conventional surface treatment (HF + silane–HF+SIL). The control (CTRL) group was not contaminated. After silane had been applied, resin cement cylinders were fabricated and light polymerized. Half of the cylinders (n=56) were tested for microshear bond strength at baseline (24 hours), and the other half after 210 days of water storage and 25 000 thermal cycles. Surface roughness, failure analysis, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDS) were performed. Statistical analysis was performed with the Kruskal-Wallis and Mann-Whitney tests for surface roughness and the 2-way ANOVA and Bonferroni post hoc tests for bond strength (α=.05). ResultsAt baseline, only SPRAY did not restore the bond strength compared with CTRL. After aging, the bond strengths of SPRAY and IVOC were lower than of CTRL (P<.05); no significant difference was found between CTRL, HPO, ULT, and HF+SIL (P>.05). EDS demonstrated the presence of carbon in the SPRAY and ULT groups, probably remnants of the evaluation paste. SEM analysis identified such remnants in the SPRAY group only. ConclusionsFor optimal bond strength between lithium disilicate and resin cement after evaluation paste use, cleaning the ceramic surface with 37% phosphoric acid, ultrasonic bath, or with hydrofluoric acid worked best.

Interfacial Diffusion Mechanism between ALD Al2O3 passivation/Cu in Direct Bonded Copper Substrate for Power Electronics

Direct bonded copper(DBC) substrate requires surface treatments for oxidation prevention and adhesion enhancement to die-attachment. Conventional surface treatment, electroless nickel immersion gold (ENIG) has a cost and environmental problems, and immersion silver is sensitive to temperature and humidity. To solve these problems, this study presents the invention of aluminum oxide (Al2O3) passivation for DBC Cu pads, which meets the requirements of oxidation prevention and adhesion enhancement to die-attachment. Ultrathin Al2O3 passivation layers (~20nm) by atomic layer deposition(ALD) were coated on DBC Cu pads for replacing conventional ENIG and immersion silver surface finishes. This paper presents bondability and interfacial diffusion mechanism between ALD Al2O3 passivation/Cu in DBC substrate.

Enhancement of corrosion resistance and antibacterial properties of PEO coated AZ91D Mg alloy by copper- and phosphate-based sealing treatment

Preparing dense coatings with both good corrosion resistance and antibacterial properties on the Mg alloys surfaces using conventional surface treatment methods is difficult. In this study, we used a solution containing Cu2+ and phosphate to seal a plasma electrolytic oxidation (PEO) coated AZ91D Mg alloy. After the treatment, a formed dense deposition layer significantly improved the corrosion resistance of the PEO-coated alloy. At the same time, the release of Cu2+ conferred excellent antibacterial properties on the Mg surface. The chemical and physical models for the sealing reaction and corrosion processes were established, providing a theoretical basis for future studies.

Stray Light Analysis and Suppression of the Visible to Terahertz Integrated Cloud Detection Optical System.

The wide-spectrum integrated imaging method can simultaneously obtain the spectral information of different spectral bands of the same target, which is conducive to the realization of the high-precision detection of target characteristics, and can simultaneously obtain more comprehensive elements such as the structure, shape, and microphysical parameters of the cloud. However, for stray light, the same surface has different characteristics at different wavelengths, and a wider spectral band means more complex and diverse sources of stray light, which renders the analysis and suppression of stray light more difficult. In this work, according to the characteristics of the visible-to-terahertz integrated optical system design scheme, the influence of material surface treatment on stray light was studied; the stray light analysis and optimization of the whole link of light transmission were carried out. For the sources of stray light in different channels, targeted suppression measures such as front baffle, field stop, special structure baffle, and reflective inner baffle were adopted. The simulation results indicate that when the off-axis field of view was greater than 10°. The point source transmittance (PST) of the terahertz channel is on the order of 10-4, the visible and infrared channels are less than 10-5, and the final terahertz PST was on the order of 10-8, while visible and infrared channels were lower than 10-11. Here, we present a method for stray light suppression based on conventional surface treatments for broadband imaging systems.

Characteristic of asphalt emulsion modified with natural rubber latex

Polymer modified asphalt emulsions offer superior performance and lifespan as compared to conventional asphalt emulsions or hot mix asphalt surface treatments, as well as reduced life cycle costs. This study’s objective was to examine the characteristics of latex-modified asphalt emulsions using a range of tests, including those for softening point, penetration, ductility, viscosity and solubility. In order to determine the optimal latex modified asphalt emulsion, latex was added into emulsion type CSS-1hP at various ratios ranging from 1 to 9 percent, with 2 percent interval while 0 percent serving as the control. From the experiments described, the best latex modified asphalt emulsion measurement was selected using a decision matrix analysis. Decision Matrix Analysis was performed to determine that asphalt emulsion with 5 percent latex is the best choice since it offers the highest quality polymer modified asphalt emulsion.

Breaking the trade off between corrosion resistance and fatigue lifetime of the coated Mg alloy through cold spraying submicron-grain Al alloy coatings

Although magnesium (Mg) alloys are the lightest among structural metals, their inadequate corrosion resistance makes them difficult to be used in energy-saving lightweight structures. Moreover, the improvement in corrosion resistance by the conventional surface treatments is always achieved at the expense of sacrificing the fatigue lifetime. In this study, high purity aluminum (Al) and AlMgSi alloy coatings were deposited on Mg alloys via an in-situ micro-forging (MF) assisted cold spray (MFCS) process for simultaneous higher corrosion resistance and longer fatigue lifetime. Besides contributing to a highly dense microstructure, the in-situ MF also greatly refines the grain of the deposited Al alloy coating to the sub-micrometer range due to the enhanced dynamic recrystallization and also generates notable compressive residual stress up to 210 MPa within the AlMgSi coating. The absence of secondary phases in the AlMgSi alloy coatings enable the coated Mg alloy with corrosion resistance, which is even better than its bulk AlMgSi counterparts. The unique combination of refined microstructure and the prominent compressive residual stress within the AlMgSi coatings, effectively delayed the crack initiation upon repeated dynamic loading, thereby leading to ∼10 times increase in the fatigue lifetime of the Mg Alloy. However, although residual stress is also generated in the submmicro-sized grained pure Al coating, the low intrinsic strength of the coating layer leads to a lower fatigue lifetime than the uncoated Mg alloy substrate. The present work is aimed to provide a facile approach to break the trade-off between corrosion resistance improvement and fatigue lifetime of the coated Mg alloys.

A critical review on effect of nanoparticles and process parameters on metallurgical properties of friction stir processing of dissimilar aluminum alloys

Friction stir welding (FSW) and friction stir processing (FSP) are unique solid-state joining and surface modification techniques that offer several advantages over conventional fusion welding and surface treatment methods. The ability to modify the microstructure and properties of the weld and surface through the control of processing parameters is a key advantage of FSW/FSP. This has led to a great deal of research on understanding the microstructural evolution during FSW/FSP. One important aspect of microstructural control in FSW/P is the development of grain structures and textures. The high strain rates and temperatures during FSW/P can lead to dynamic recrystallization and the formation of refined and homogeneous grain structures. The degree of grain refinement and texture development can be controlled through the selection of processing parameters such as tool geometry, rotation speed, traverse speed, and applied pressure. Another important aspect of microstructural control in FSW/P is the formation of phases, phase transformations, and precipitation. The ability to control grain structures, phases, and IMCs, as well as the potential for local refinement and the formation of MMCs, makes FSW/P an attractive option for a wide range of applications. Continued research and development will be critical for further advancing the capabilities and potential of FSW/P.

Access to high-performance Li-rich layered oxide cathodes via ammonium phosphate surface treatment.

Ammonium phosphate ((NH4)3PO4) has been first used as a surface treatment reagent for Li-rich cathode materials. Compared to the conventional surface treatment, the samples treated with (NH4)3PO4 exhibit an ultra-high initial Coulomb efficiency of 98.0% and excellent cycling stability. This is mainly attributed to the simultaneous construction of surface integrated structures, including oxygen vacancies, spinel phases, and Li3PO4 coating. This study demonstrates the effectiveness of ammonium phosphate surface treatment and provides a new idea for designing other cathode materials.

Effect mechanism of cryogenic treatment on ferroalloy and nonferrous alloy and their weldments: A review

As a different step from conventional heat treatment, cryogenic treatment played a very important role in improving the microstructure and properties of metals. The effect mechanism of cryogenic treatment on steel and non-ferrous metals and their weldments was reviewed. The influence parameters of cryogenic treatment were discussed, and the influence of cryogenic treatment on microstructure was analyzed, which led to the change of tensile strength, corrosion resistance, fatigue resistance, wear resistance and other properties. In addition, the relationship between cryogenic treatment and heat treatment were also discussed. On this basis, the influence mechanism of cryogenic treatment on metal materials was explained from the three aspects of crystal defect, phase transformation and precipitated phase, and the reasons for these phenomena were more deeply understood after cryogenic treatment. On the basis of cryogenic treatment, the method combining with conventional heat treatment and surface treatment was put forward, which provided a new way for obtaining high performance materials. It could be widely used in metal forming and other fields, and provide a broader vision for material post-processing through the prediction of numerical simulation.

Enhancement of Mechanical Properties and Corrosion Resistance of Cast Iron Alloy Using CO2 Laser Surface Treatment

This work aimed to study the effect of laser surface treatment on the mechanical characteristics and corrosion behaviour of grey cast iron type A159. Many technical applications used conventional surface treatment, but laser surface hardening has recently been used to enhance the surface properties of many alloys. The mechanical characteristics, including microstructure, microhardness, and wear resistance of A159 grey cast iron, were studied, in addition to corrosion behaviour. The experimental laser parameters in this work were 0.9, 1.2, and 1.5 KW power with continuous wave carbon dioxide lasers with scanning speeds of 10 and 12 mm/s were used. The results found that phase-transitional alterations in microstructure were influenced by laser therapy. Also, the microhardness increased with increasing power, with the maximum reaching approximately 950 HV while the base metal has an average of approximately 260 HV. Also, we found the power laser increased corrosion resistance by lowering the corrosion rate (CR) from 21.10 for the untreated sample to 1.02 (m.p.y.), additionally, corrosion protection efficiency (CPE) increased to 95.27 percent. On the other hand, the wear test revealed that mass loss decreased as laser surface treatment power increased; it reached 0.19 g for the laser-treated samples, compared to 1.25 g for the base metal after the 50th minute of the wear experiment.

Dependency of Ag wetting on the oxygen nonstoichiometry of oxide surfaces

Oxide substrates are frequently modified to have either an oxygen deficiency or excess to synthesize a completely continuous, ultrathin metal layer on them by strengthening the metal–oxide adhesion. However, conventional surface treatments using ionic irradiation inevitably induce detrimental structural irregularities, along with chemical modification, on the surface of oxide substrates. This study explores the dependency of Ag wetting on the oxygen deficiency and excess on the surface of a ZnO substrate. The favorable contribution of the increased oxygen deficiency and excess of ZnO surfaces in improving Ag wetting during the inceptive growth stages is evidenced by both experimental results and numerical interpretations. This improved Ag wetting is attributed to a significant reduction in free energy at the Ag–ZnO interfaces, whereas pinholes remain in thicker Ag layers on the ZnO surfaces. This finding extends earlier studies, reporting a favorable role of an increased oxygen deficiency on Ag wetting, with the point that oxygen excess beyond a threshold value is also helpful in improving Ag wetting. Our findings redefine the underlying Ag wetting mechanisms of the nonstoichiometric surface of oxide substrates. Moreover, the study provides guidelines for implementing a continuous ultrathin Ag layer while avoiding ion-induced damage to the oxide substrates.

Dental implants with electrochemical nanopattern formation to increase osseointegration

An electrochemical nanopattern formation (ENF) surface treatment was developed to overcome the limitations of conventional surface treatments. This study aimed to evaluate the cytocompatibility and preclinical efficacy of the newly developed ENF surfaces in comparison to conventional surfaces. The cytocompatibility of human mesenchymal stem cells, degree of bone formation, bone-to-implant contact (BIC) ratio, and implant stability quotient (ISQ) were investigated using rabbit and beagle models. Overall, the ENF surfaces showed greater cytocompatibility than other surfaces. The ISQs of implants in rabbit tibias showed that ENF surfaces provided greater stability than other surfaces. In contrast, the ISQs of implants in beagle mandibles were similar for ENF and sandblasted large-grit acid-etched (SLA) surfaces. In the rabbit model, the degree of bone formation and BIC ratio were significantly higher for ENF surfaces than for other surfaces. However, the removal torque (RT) during implant removal was significantly higher for SLA surfaces than ENF surfaces. Thus, it was confirmed that ENF-treated dental implants can replace conventional implants, but further research is required to improve the surface roughness to increase the RT.

Experimental Study on the Slip Behaviour of Stainless Steel High-Strength Bolted Connections with a New Surface Treatment.

The conventional surface treatments on stainless steel plates yield slip factors less than the required value for a friction grip, which hinders the application of stainless steel high-strength bolts. The slip factor and the treatment process of stainless steel surfaces are not clearly specified in most of the existing design codes. Existing studies also show different slip factors from similarly treated surfaces. In this paper, a new surface treatment is proposed: the two touching surfaces of the bolted connection are grit-blasted on one side and coated with high-velocity oxygen fuel (HVOF) on the other side. The slip behaviour of the new method was compared with four conventional methods. The roughness and hardness of different surfaces were measured prior to a total of 30 slip tests where the slip factors of multiple stainless steel surfaces were tested. It was shown that the new proposed surface treatment method can yield a slip factor of 0.61, much higher than the conventional surface treatments, meeting the requirements as a slip-resistant connection. The preload relaxation of stainless steel high-strength bolts was also monitored and compared to standard grade 10.9 high-strength bolts. We found that the preload relaxation in stainless steel high-strength bolts is negligible.