Plating Process Research Articles

Boiling heat transfer enhancement by a pair of elastic plates

Boiling heat transfer enhancement is essential for energy utilization. Traditional passive boiling enhancement methods aiming at bubble departure promotion usually depend on the modulation of surface tension force by surface modification. However, the limited driven force which benefits bubble departure cannot help the further improvement of heat transfer performance facing the increased heat dissipation amounts. In this paper, a novel boiling enhancement method using a pair of elastic plates (i.e., flexible parallel plates made of stainless steel) which promotes bubble departure by its swing effect for boiling on Pt wire in confined space is proposed and investigated. Compared to boiling with a pair of rigid plates (the thickness of 0.5 mm and the length of 12 mm), the heat transfer coefficient (HTC) is improved by 55.8% of those with elastic plates (the thickness of 0.01 mm and the length of 12 mm).Periodic expansion and recovery process of plates coupling bubble dynamics is observed and studied. Experimental results indicate that elastic plates enhance boiling heat transfer performance significantly by smaller bubble departure diameter and lower wall superheat at the same wall heat flux. A correlation for bubble departure diameter prediction in elastic channel is proposed which matches well with experimental results. It is found that the stronger pumping effect induced by higher swing rate of plates enhance HTC significantly. The mechanism where expansion process of plates promotes bubble departure while its subsequent recovery process benefits the supply of the cold liquid is verified by simulation. This study proposes a new approach for boiling heat transfer enhancement by inducing the energy exchange between bubbles and elastic plates, and provides theoretical and technical support for boiling study based on flexible materials.

Experimental and Numerical Investigation of the Fracturing Process of Marble Plates with a Pair of Twin Cylindrical Holes Subjected to Uniaxial Compression

Experimental and Numerical Investigation of the Fracturing Process of Marble Plates with a Pair of Twin Cylindrical Holes Subjected to Uniaxial Compression

Air-coupled transducer tilted C-scan for delamination introduced during the manufacturing process in CFRP plates

ABSTRACT Carbon fibre reinforced polymers (CFRPs) have gained attention as viable substitutes for conventional metals and alloys in weight-sensitive applications like aerospace, primarily because of their outstanding strength-to-weight characteristics. Nevertheless, these materials are susceptible to intricate and challenging-to-anticipate sub-surface impairments, such as delamination after certain impacts. Non-destructive ultrasonic testing (NDT) is a widely employed technique for examining workpieces’ properties. Nonetheless, conventional ultrasonic testing faces significant constraints due to the necessity of physically coupling ultrasonic transducers to the test medium, typically involving substances like liquid and gel, which could cause unnecessary corrosion and pollution on composite materials. This study proposed a tilted non-contact C-scan detection on carbon composite plates with internal delamination based on air-coupled transducers (ACT). By introducing a tilted C-scan method, the subtle pre-fabricated internal impurities can be detected.

ИСПОЛЬЗОВАНИЕ ДОБАВОК ПИРИДИНОВЫХ СОЛЕЙ ДЛЯ ПОЛУЧЕНИЯ БЛЕСТЯЩИХ НИКЕЛЕВЫХ ПОКРЫТИЙ

The process of electrochemical nickel plating and the effect of the process of nickel deposition are considered

ПОЛУЧЕНИЕ БЛЕСТЯЩИХ НИКЕЛЕВЫХ ПОКРЫТИЙ В ПРИСУТСТВИИ ТРИФТОРУКСУСНОЙ КИСЛОТЫ

The influence of a fluorine-containing compound on the process of electrochemical nickel plating in sulfate and acetate-chloride electrolytes is considered

ВЛИЯНИЕ 2-АМИНО-1,3-ТИАЗОЛОН-4 ХЛОРИДА НА ПРОЦЕСС ЭЛЕКТРОХИМИЧЕСКОГО НИКЕЛИРОВАНИЯ

The effect of the organic additive 2-amino-1,3-thiazolone-4 chloride on the electrochemical nickel plat-ing process has been studied. It is shown that this organic compound is capable of having a gloss-forming effect with high current output

ВЛИЯНИЕ ДИГИДРОКВЕРЦЕТИНА НА КАЧЕСТВО НИКЕЛЕВЫХ ПОКРЫТИЙ В СУЛЬФАТНОМ ЭЛЕКТРОЛИТЕ

The influence of dihydroquercetin and the electrolysis mode in a sulfate electrolyte on the nickel plat-ing process, as well as the quality of nickel coatings, was studied

Formation and Evolution of Interfacial Structure in Al–Si–Mg/Stainless Steel Bimetals during Hot-Dipping Process

Understanding trends in the formation of the intermetallic compound (IMC) layer in Al/Fe bimetallic composites can aid in significantly improving their mechanical properties. However, it is currently challenging to predict IMC layer formation during hot-dip aluminizing. Furthermore, the results from previous studies are difficult to compare owing to the variation in the process parameters used. Therefore, to understand how temperatures and holding times affect the thickness and hardness properties of IMC layers, we investigated the interfacial properties of aluminized stainless steel in molten Al-Si-Mg. AISI 420 stainless steel was hot-dip aluminized in an Al–Si–Mg alloy melt for 10–120 min at four different temperatures: 700, 750, 800, and 850 °C. Morphology, type, and element distribution of the phases formed in the reaction layer and the reduction rate of the aluminizing process were studied. Notably, while the reaction layer thickness increased with increasing aluminizing temperature when the holding time was low, long-term reaction caused the reaction layer to become thicker at lower temperatures. The mechanism of this morphological transformation is discussed. The results demonstrated effective trends in controlling the morphology of the intermetallic compound layer with respect to various hot-dip Al plating process parameters.

Passivation of cold-sprayed zinc-coated steel bars in simulated concrete pore solution

Hot-dip galvanized coating is proved to be effective in preventing chloride ion induced corrosion on steel bars, however, highly-toxic substances generated during the plating process seriously pollute the surrounding environment. Cold-sprayed zinc as an environment-friendly technology is an alternative to the hot-dip galvanized technology, but it has not been applied to steel bars in the alkaline environment of concrete. This study first fabricated the cold-sprayed zinc-coated steel bars, and then investigated the influences of Ca2+ concentration and pH on the passivation of zinc-coated steel bars in the simulated concrete pore solutions through electrochemical tests, microstructure examination, and element composition analysis. The experimental results show that passive film can be generated on the surface of cold-sprayed zinc-coated specimens in the simulated concrete pore solutions with pH = 12.5 and Ca2+ concentration above 0.8 g/L, but Ca2+ concentration determines the density and quality of the passive film. The passive film can resist the attack of chloride ions up to 0.2 mol/L. Compared with hot-dip galvanized coating, more large-sized and compacted crystals are generated on the surface of cold-sprayed zinc coating. Thus, it is feasible to apply cold-sprayed zinc technology to provide corrosion protection for steel bars in the concrete.

All-fiber 3 kW LP02 laser output based on long-period fiber grating for precise welding

An innovative all-fiber mode converter specifically designed for high-power fiber lasers is introduced. The mode converter relies on the coupling theory of long-period fiber gratings (LPFGs) and involves the fabrication of a LPFG, where the performance is meticulously studied by examining various fabrication parameters. The LPFG is integrated into a high-power fiber laser system to achieve efficient conversion from the LP01 mode to the LP02 mode with a conversion ratio of 90 % and a low transmission loss of only 0.088 dB. Under a 3.03 kW laser output, the LP02 fiber laser exhibits a remarkable laser-to-raman peak intensity ratio, which is 15.98 dB higher than that of the signal-mode fiber laser. Furthermore, during the welding process of a thick aluminum plate, the LP02 fiber laser demonstrates a significant increase of 1.2 times in the depth of the weld pool morphology compared to the signal-mode fiber laser, particularly evident when operating at a laser welding head speed of 100 mm/s. The mode converter with LPFG exhibits lower insertion loss, enhanced power-handling capacity, making it ideal for diverse high-power fiber laser applications with promising practical prospects.

Effect of Nb interlayer thickness on interfacial products and mechanical properties of Ti–6Al–4V/EH690 steel clad plate by vacuum hot rolling

The high content of alloying elements in Ti alloys and high-strength steels, combined with the requirement for quenching and tempering heat treatment during the fabrication process of the clad plate, leads to complex interfacial products and poor bonding properties. An Nb interlayer was introduced to enhance the mechanical properties of Ti alloy/steel clad plates. This work investigated the effect of Nb interlayers with initial thicknesses of 10, 25, and 50 μm on the evolution of interfacial products and bonding properties. The results indicated that when the interlayer was thin (10 μm thick), the diffusion of Ti, Fe, and C in the matrix and clad materials could not be completely inhibited due to the uneven distribution of the Nb interlayer at the interface. TiC, NbC, Nb2C, and Fe2Nb were detected at the Nb/steel interface. With the thickness of the interlayer increased (reaching 25 μm or 50 μm), the influence of uneven deformation on the interlayer was weakened, and the Nb/steel interface was composed of Nb2C and Fe2Nb. The tensile shear test indicated that the fracture occurred at the Nb/steel interface and the Nb interlayer. The plasticity of the micrometer Nb interlayer decreased with the increase in interlayer thickness. Therefore, more cracks and brittle fracture characteristics were observed in the fracture surface of the 50 μm thick Nb interlayer sample. The clad interface with a 25 μm thick Nb interlayer exhibited the highest interfacial shear strength of 295 MPa due to the few intermetallic compounds (IMCs) at the Nb/Steel interface and the excellent plasticity of the Nb interlayer.

Research on Key Technologies for Optimization of Forming Parameters of Aluminum Alloy Hood Outer Panel

At present, computer technology and finite element software analysis technology have been widely used in the stamping and forming process of aluminum alloy hood outer plate to predict the possible quality defects in the stamping process, and effectively improve the quality and production efficiency of parts. The stamping and forming of the outer plate of the automobile aluminum alloy hood is a highly nonlinear process, and its forming quality involves many forming factors, if the variable design is not reasonable, it may lead to quality defects such as wrinkles or cracks of the molded parts. Due to the relatively complex shape and structure of the aluminum alloy hood outer plate and its high requirements for the quality of forming, it is difficult to obtain the optimal process parameters in a short time if the finite element software simulation optimization is carried out manually. The machine learning algorithm is applied to the research on the stamping and forming of the outer plate of the aluminum alloy hood, and the multi-objective genetic algorithm is used to optimize the stamping process parameters of the covers, which can meet the maximum thinning rate of the formed parts and control the rebound of the formed parts to a certain extent. How to combine machine learning algorithms with finite element simulations to reasonably adjust the process parameters in the stamping and forming process by using machine learning algorithms to meet the forming quality requirements of aluminum alloy hood outer plate has always been a research hotspot and difficulty in the field of aluminum alloy hood outer plate stamping.

Plating Al coating on high-strength steel in chloroaluminate ionic liquid under pulse current modes

Aluminum coating is a potential candidate for cadmium coating replacement due to its excellent corrosion resistance and nontoxicity. Among the fabrication methods of Al coating, plating Al via ionic liquids has drawn major attention of researchers because of the superiority of controllability, stability and low energy consumption. However, the evolution rules of plating aluminum on high-strength steel via pulse current modes at room temperature requires deeper investigation. In this work, pulse current density and pulse duty factor are regulated to reveal the plating patterns of Al on 300M high-strength steel in AlCl3-EMIC (2:1 in mole) ionic liquid. It is found that higher current density can significantly facilitate the nucleation of Al grains and the compactness of morphology, while an enlarged pulse duty factor tends to result in more regular Al crystals. When the current density and the pulse duty factor are fixed at 20 mA cm−2 and 80 %, the densest and most uniform aluminum coating is obtained. The component of Al coating is verified to be pure Al crystals with good adhesion and the plating process achieves a high current efficiency of 97.27 %. Under the protection of Al coating, the impedance and galvanic corrosion current density of 300M steel substrate are optimized by two orders of magnitude, and the corrosion current density is markedly decreased from 5.58 μA cm−2 to 0.77 μA cm−2.

Development and evaluation of an artificial intelligence for bacterial growth monitoring in clinical bacteriology.

In clinical bacteriology laboratories, reading and processing of sterile plates remain a significant part of the routine workload (30%-40% of the plates). Here, an algorithm was developed for bacterial growth detection starting with any type of specimens and using the most common media in bacteriology. The growth prediction performance of the algorithm for automatic processing of sterile plates was evaluated not only at 18-24 h and 48 h but also at earlier timepoints toward the development of an early growth monitoring system. A total of 3,844 plates inoculated with representative clinical specimens were used. The plates were imaged 15 times, and two different microbiologists read the images randomly and independently, creating 99,944 human ground truths. The algorithm was able, at 48 h, to discriminate growth from no growth with a sensitivity of 99.80% (five false-negative [FN] plates out of 3,844) and a specificity of 91.97%. At 24 h, sensitivity and specificity reached 99.08% and 93.37%, respectively. Interestingly, during human truth reading, growth was reported as early as 4 h, while at 6 h, half of the positive plates were already showing some growth. In this context, automated early growth monitoring in case of normally sterile samples is envisioned to provide added value to the microbiologists, enabling them to prioritize reading and to communicate early detection of bacterial growth to the clinicians.

Sustainable formaldehyde-free copper electroless plating on carbon-epoxy substrates

In this paper, a formaldehyde-free copper electroless plating process was optimized using statistical analysis (Design of Experiment) in order to maximize the adhesion and the electrical conductivity when deposited on carbon-epoxy substrates. The coatings' morphologies, the electrical resistance, and the adhesion vary significantly as function of electroless plating parameters, but among the selected processing parameters, (pH of the electroless solution, temperature, concentration of reducing agent (glyoxylic acid), and concentration of complexing agent (EDTA)) only the temperature and the concentration of the reducing agent resulted to be influencing factors for the deposition process. A multi-objective optimization approach allowed to set the electroless process parameters in order to obtain optimized coatings presenting improved adhesion (scratch test’s critical load CL3 > 30 N) and electrical conductivity (Rs = 1.91 × 10–2 Ω/sq).

Improving soft X-ray imaging contrast uniformity of 50nm Au zone plate by optimizing pulse plating

The Fresnel zone plate plays a pivotal role in X-ray imaging systems, directly influencing the uniformity of imaging contrast. Achieving uniform imaging contrast imposes stringent requirements on the linewidth and height uniformity of the zone plate. The current mainstream method for zone plate fabrication involves utilizing electron beam lithography in conjunction with electroplating. However, in structures with large aspect ratios, precise deposition of gold to the bottom of the trench through electroplating becomes increasingly challenging to control. In this study, we employed a pulse plating process to enhance the uniformity of the plating height. Detailed investigations were conducted to analyze the effects of pulse current density, pulse duty cycle, and pulse frequency on plating height. Utilizing pulse plating, we successfully fabricated a zone plate with an outermost width of 50 nm and a thickness of approximately 245 nm. Structural analysis showed that the plating height uniformity is improved to better than 5%. The high uniformity imaging pattern was obtained by using the Siemens star test pattern at the soft x-ray imaging station at NSRL. The spatial resolution was down to 50 nm.

Analysis of the regulatory database to determine the criteria for the effectiveness of structural and technological solutions for the installation of structural slabs

This article is devoted to the analysis of the regulatory framework in the context of determining the criteria for the effectiveness of structural and technological solutions for the installation of structural slabs. The study is aimed at identifying the regulatory requirements and standards that regulate the process of installation of the covering, in particular structural plates. The authors highlight current issues related to the effectiveness of constructions and installation technologies, as well as conduct a systematic review of the literature and analyze existing norms and standards. Particular attention is paid to defining the key criteria that determine the efficiency and reliability of the installation of structural plates. The results of the study can be useful for specialists in the field of construction design, architectural design and the construction industry. The analysis of the regulatory framework allows modern practitioners and researchers to better understand the requirements for structures and contributes to the further development of standards in the field of installation of structural slabs. Against the background of the rapid development of the construction industry and constant technological evolution in the field of building structures, special attention is devoted to the analysis of the regulatory framework for determining the criteria for the effectiveness of structural and technological solutions, in particular, when installing structural slabs. The article begins with substantiating the relevance of the topic, based on the need to optimize and improve construction processes. The authors identify problems and challenges that often arise in connection with the installation of structural plates, and argue the need for a thorough analysis of regulatory documents. In the future, a systematic review of the literature and existing national and international standards regulating the installation process of structural plates is carried out. Special attention is paid to identifying inconsistencies or gaps in existing regulatory documents and the need for their clarification. The key aspect of the extended analysis is the determination of efficiency and reliability criteria for the installation of structural plates. The authors consider technical and operational aspects, taking into account the impact of the environment and the requirements for the durability of structures. The main results of the research can be useful for practicing engineers, architects and specialists in the construction industry. The conclusions and recommendations of the article can serve as a basis for further scientific research in the field of improvement of regulatory requirements and standards for improving the quality and safety of the installation of structural slabs.

Precision finishing of nickel-phosphorus plated carbon fibre reinforced polymer

Carbon fibre reinforced polymer is a lightweight material having superior mechanical properties and thermal stability and a promising material for light-weight mirrors for space applications. In this work, the surface of carbon fibre reinforced polymer is electroless nickel-phosphorus plated. The morphologies of the substrate and as-plated surfaces are compared. The surface roughness of the plated surface showed a significant reduction after the plating process. The elemental composition and phase of the as-plated sample are studied. The plated carbon fibre reinforced polymer surface is polished using an elastic tool with a diamond abrasive pad having grit sizes of 45 and 9 μm. The topography and the morphology of the finished surface are analysed for understanding the material removal process. A minimum Ra of 48 nm is obtained on the plated surface after 28 min of polishing. At a finishing rate of 18.17 nm/min, a 91.4% drop in Ra is achieved in comparison to a plated surface.

Polymer-based passive layer to stabilize zinc anode in aqueous electrolyte

Metallic zinc holds promise as a cost-effective and scalable material for secondary energy storage applications. However, its inherent reversibility issues hinder its practical implementation. Among various strategies, interface engineering has emerged as a promising approach to enhance the reversibility of zinc anodes. Herein we introduce an innovative method involving the parallel deposition of poly(acrylic acid) (PAA) and zinc metal, creating a composite layer of polymer and zinc, denoted as Zn-PAA. This unique Zn-PAA layer deposition technique remarkably enhances interfacial behavior, ensuring superior cyclic stability in symmetric cells. Moreover, the Zn-PAA layer reduces polarization effects and effectively mitigates interface alterations during plating and stripping processes resulting in increased interface stability. This study highlights the potential of simultaneous electropolymerisation and zinc deposition as a promising strategy to coat and densify interface on zinc anode with intertangled matrix of zinc and polymer for improving the performance and stability of zinc anodes in batteries.

The effect of thermomechanical treatment on the electrodeposited Invar alloy for FMM

Fine metal masks (FMMs), which are applied to manufacture next-generation organic light-emitting diode (OLED) displays with ultra-high definition (UHD) or higher, must have thicknesses of <10 μm to eliminate shadow zones. To manufacture FMMs with a thickness of 10 μm or less, a bottom-up electroplating process must be applied. The minimum coefficient of thermal expansion (CTE) of the as-deposited electroplated Invar alloy is 4 ppm; subsequent thermal treatment can lead to a CTE of zero. However, sample conditions such as surface wrinkles and edge curls may appear during this thermal treatment process. The effect of varying treatment parameters, including pressure and temperature, on the shape of the electrodeposited Invar alloy is investigated in this study by performing a thermomechanical treatment that can regulate the ultrathin FMM shape. Depending on the Ni composition, the electrodeposited Invar alloy may exist as a singular α-BCC phase or a mixed γ-FCC phase during electrodeposition. During thermomechanical treatment, a phase transformation occurs from the electrodeposited α-BCC phase to the γ”-FCC phase, and wrinkles occur owing to uneven volume change. Additionally, curls are formed owing to CTE variations according to the ratio of phases from the electrodeposition surface to the final surface varies during the plating process. Based on these results, process conditions that facilitate shape control of ultra-thin electroplated FeNi alloys were proposed.